1 PP 1 ill! 1 1 l! 111! lllliii iftll llilf iliilifliiliillliiiliilillii^i ' II iifiij iiji in lillihliliiihllrlrif ill $!ltill iiHtsBBB^^H^H HBIllil 1 fill Hll !ll*ilt 111 mi til is i frfo UNIVERSITY OF CALIFORNIA DEPARTMENT OF EDUCATION GIFT OF THE PUBLISHER No. s Education Department NEW GRAMMAR SCHOOL ARITHMETIC BY JOHN H. WALSH ASSOCIATE SUPERINTENDENT OF SCHOOLS, THE CITY OF NEW YORK BOSTON, U.S.A. D. C. HEATH & CO., PUBLISHERS 1905 Copyright, 1895 and 1903, By JOHN H. WALSH. INTRODUCTION. The New Grammar School Arithmetic forms with the New Primary Arithmetic a complete course in elementary school mathematics. Each of the first four chapters of the New Grammar School Arithmetic provides for a half year, beginning with advanced matter, which is followed by a review and an extension of the topics of the preceding grades. Each of the next two chapters (V and VI) contains arithmetic work for a year, which should be supplemented by portions of the algebraic and geometrical material of Chapters VII and VIII. It is recommended that at least a portion of the work in equations of Chapter VII should precede the study of Chapter V. Among the special features of the New Grammar School Arithmetic are the number and the variety of the problems ; the systematic reviews, which cover oral and written drill work even in the fundamental operations ; the attention paid to short, direct, business methods of computation ; and the spiral handling of the various topics. iii 548N48 CONTENTS. CHAPTER I. PAGES Mixed Numbers 1 to 16 Addition, Subtraction, Multiplication, Division (Common Denominators determined by inspection). Review of Simple Numbers 17 to 24 Notation and Numeration, Special Drills, Fundamental Processes. Decimals (three places) 25 to 32 Addition and Subtraction, Multiplication and Division by an Integer. United States Money . . . . . . . . 32 to 43 Fractional Parts of a Dollar, Division of United States Money. Denominate Numbers 43 to 45 Time, Dry and Liquid Measures, Avoirdupois Weight, Miscellaneous Examples. Measurements 46 to 49 The Area of Rectangles. Bills 50 Miscellaneous 51 to 58 Approximate Answers, Review Problems. CHAPTER II. Fractions 59 to 84 Greatest Common Divisor, Least Common Multiple, Addition and Subtraction of Fractions, Cancellation, Ratio, Multiplication and Division of Fractions. Decimals 84 to 91 Multiplication of Decimals, Division of Decimals. v vi Contents. PAGES United States Monet , 92 to 93 Fractional Parts of a Dollar Denominate Numbers 94 to 99 Reduction, Addition, Subtraction, Multiplication, and Division. Measurements 99 to 101 Areas and Surfaces. Bills 101 to 102 Review of Simple Numbers 102 to 118 Short Methods, Sight Exercises, Sight Approxima- tions, Review Problems. CHAPTER III. Decimals 119 to 132 Notation and Numeration, Reduction, Addition, Sub- traction, Multiplication, Division. United States Money . . . . . . . 132 to 133 Denominate Numbers 133 to 139 Reduction, Addition, Subtraction, Multiplication, Division (two denominations). Measurements 139 to 144 Areas of Rectangles, Areas of Right-angled Triangles. Bills 144 to 145 Percentage 145 to 147 Interest 148 to 152 Review of Simple Numbers and Fractions . . 152 to 162 Sight Approximations, Special Drills, Cancellation, Ratio, Short Methods, Review Fractions. Miscellaneous Problems 162 to 172 Oral and Written. CHAPTER IV. Denominate Numbers 173 to 189 Reduction, Descending and Ascending, Compound Addition, Subtraction, Multiplication, and Division, Avoirdupois Weight, Time between Dates. Contents. t \s:\: »/, vhV i Percentage . • 189 to 194 Applications and Simple Interest. Measurements ......... 195 to 209 Area of Rectangles, Square Measure, Solid Contents, Cubic Measure, Surfaces of Rectangular Solids, Angles, Triangles, Quadrilaterals. Review op Simple Numbers and Fractions . . 209 to 218 . Special Drills, Sight Approximations, Fundamental Processes, Cancellation, Review Fractions, Review Decimals. Review Problems 218 to 228 Miscellaneous, Oral, Written. CHAPTER V. Percentage 229 to 276 Finding Percentage, Base, Rate ; Commission, Insur- ance, Duties, Taxes, Profit and Loss, Commercial Discount, Interest, Partial Payments, Bank Discount, Interest by Aliquot Parts. Denominate Numbers 277 to 291 Reduction Descending and Ascending, Addition, Sub- traction, Multiplication, Division, Review. Review of Simple Numbers, Fractions, and Decimals 291 to 309 CHAPTER VI. Ratio and Proportion , 310 to 328 Ratio, Proportion, Partitive Proportion, Partnership, Compound Proportion. Involution and Evolution 328 to 338 Square Root, Applications of Square Root, Cube Root. Mensuration 339 to 357 The Circle, Areas of Circles, Areas of Triangles, Areas of Quadrilaterals, Surfaces of Prisms and Cylinders, Surfaces of Pyramids and Cones, Volumes of Prisms and Pyramids, Volumes of Cylinders and Cones, Sur- face of Sphere, Volume of Sphere, Circular Measure. viii . Contents. ! ',' < f '< r < ' ', ' , . ' t ' PAGS8 Longitude and Solar Time . . . . . 358 to 363 Standard Time, Solar Time. Review Problems ........ 363 to 366 Miscellaneous, Oral, Written. Stocks and Bonds 367 to 372 Domestic Exchange ' . . . 373 to 377 Sight Drafts, Time Drafts, Bills of Exchange. Interest . . . 378 to 380 Compound Interest, Annual Interest. Metric System 380 to 384 Review Problems 384 to 414 Special Drills, Review of Fractions, Review of De- nominate Numbers, Review of Commercial Discount, Review of Interest, Review of Bank Discount, Exact Interest, Miscellaneous — Oral and Written. CHAPTER VII. Algebraic Equations of One Unknown Quantity . 415 to 439 Coefficients, Clearing of Fractions, Positive and Nega- tive Quantities, Addition, Subtraction, Removing Parentheses. Two Unknown Quantities 440 to 445 Three Unknown Quantities 445 to 449 Multiplication and Division 449 to 469 Exponents, and Terms. Factoring 460 to 467 Fractions 468 to 470 Quadratics 471 to 479 CHAPTER VIII. Geometry 480 to 503 Lines, Angles, Triangles, Quadrilaterals, Circles, Problems in Construction, Calculating Heights and Distances. SUGGESTIONS TO TEACHERS. Additions and Omissions. — The teacher should freely supplement the work of the text-book when it is found necessary to do so ; and the pupils should not be required to continue the work under any topic after they fully understand it, even though they may not have solved all the problems given in connection therewith. Oral and Written Work. —The heading "Written Problems" is merely a general direction, and it should be disregarded by the teacher when the pupils are able to do the work " mentally." The use of the pencil should be required only so far as it may be necessary. It is a pedagogical mistake to insist that the brighter pupils of a class should set down a number of figures that they do not need. As an occasional exercise, the pupils may be directed to give all the work required to solve a problem, and to make a written explanation of each step in the solution ; but it should be the teacher's aim to have the majority of the examples done with as great rapidity as is consistent with abso- lute correctness. It will be found that, as a rule, the quickest workers are the most accurate. Conduct of the Recitation. —It is often advisable, for some pur- poses, to divide an arithmetic class into two sections, even where the pupils are nearly equal in attainments. The members of one sec- tion may work examples from their books while the others write the answers to oral problems given by the teacher, etc. Where a class is thus taught in two divisions, the members of each should sit in alternate rows, extending from the front of the room to the rear. Seated in this way each pupil is doing a different kind of work from those on the right and the left, and he does not have the temptation of a neighbor's work to lead him to compare answers. To save time, explanations of new subjects may be given to the whole class ; but much of the arithmetic work should be done in " sec- tions," one of which is under the immediate direction of the teacher, while the other is employed in "seat" work. The "seat" work of pupils of the more advanced classes should consist largely of problems solved without assistance. Especial pains have been taken to grade the Suggestions to Teachers. .'PfdbjeHja sdas-to have' none beyond the capacity of the average pupil. It is not necessary that all the members of a division should work the same problems at a given time, or the same number of problems, or that a new topic should be postponed until all of the previous problems have been solved. Whenever it is possible, each of the members of the division work- ing under the teacher's immediate direction should take part in all the work done. In mental arithmetic, for instance, while only a few may be called upon for explanations, all of the pupils should write the answers to each question. The same is true of much of the sight work, the approximations, some of the special drills, etc. Drills and Sight Work. — To secure reasonable rapidity, it is necessary to have regular and systematic drills. These should be employed frequently, but should not last longer than five or ten minutes. A page of special sight drills is given in each chapter. These may also be used in oral problems. It often happens that as pupils go forward in school they lose much of the readiness in oral and written work that they possessed in the lower grades, owing to the neglect of their teachers to continue to require quick, accurate review work in the operations previously taught. In this book these special drills follow the plan of the combinations of the earlier book, but gradually grow more difficult. They should first be used as sight exercises, either from the books or from the blackboard. To secure valuable results from drill exercises, the utmost prompt- ness in answers should be required. Language. — While the use of correct language should be insisted upon in all lessons, children should not be required in arithmetic to give all answers in "complete sentences." Especially in the drills, it is important that the results be expressed in the fewest possible words. The teacher should be careful always to employ exact arith- metical language and to require it from the pupils. Objective Illustrations.— The chief reason for the use of objects in the study of arithmetic is to enable pupils to work without them. While counters, weights and measures, diagrams, or the like are neces- sary at the beginning of some topics, it is important to discontinue their use as soon as the pupil is able to proceed without their aid. Approximate Answers. — An important drill is furnished in the "approximations" (see Arts. 104, 180, 238, etc.). Pupils should be required in much of their written work to estimate the result before beginning to solve a problem with the pencil. Besides preventing an Suggestions to Teachers, , xT absurd answer, this practice will also have the effect of causing 'a pupil to see what processes are necessary. In too many instances, work upon a problem is commenced before the conditions are grasped ; this will be less likely to occur in the case of one who has carefully "estimated" the answer. The pupil will frequently find, also, that he can obtain the correct result without using his pencil. Indicating Operations. — It is a good practice to require pupils to indicate by signs all of the processes necessary to the solution of a problem, before performing any of the operations. This frequently enables a pupil to shorten his work by cancellation, etc. In the case of problems whose solution requires tedious processes, some teachers do not require their pupils to do more than to indicate the operations. It is to be feared that much of the lack of facility in adding, multiply- ing, etc., found in the pupils of the higher classes is due to this desire to make work pleasant. Sight Exercises. — Many pupils who find it difficult to solve prob- lems read to them readily make the necessary calculations without a pencil when they have the numbers before them on the blackboard, or in their books. It may be found advisable to have a class first solve the whole of a given set of oral problems from their books, and at a later lesson write the answer to each question after it has been read by the teacher. In the case of sight exercises too difficult to be solved mentally, the set might be taken up one at a time by individual pupils, after which the pupils might be required to write answers " at sight " at a signal from the teacher. If the exercises are on the blackboard, the teacher might use a pointer to indicate the example whose answer was desired, not following the order in which they appeared on the blackboard. A similar method might be employed in sight work done from the books. NEW GEAMMAK SCHOOL ARITHMETIC. ~tto* CHAPTER L PAGK8 Mixed Numbers 1 to 16 Addition, Subtraction, Multiplication, Division (Common Denominators determined by inspection). Review of Simple Numbers . . . . . . 17 to 24 Notation and Numeration, Special Drills, Fundamental Processes. Decimals (three places) 25 to 32 Addition and Subtraction, Multiplication and Division by an Integer. United States Monet 32 to 43 Fractional Parts of a Dollar, Division of United States Money. Denominate Numbers 43 to 45 Time, Dry and Liquid Measures, Avoirdupois Weight, Miscellaneous Examples. Measurements 46 to 49 The Area of Rectangles. Bills 50 to 51 Miscellaneous 51 to 58 Approximate Answers, Review Problems. MIXED NUMBERS. 1. Preliminary Exercises. How many halves in 1 ? How many fourths in 1 ? Six halves = ? 12 fourths = ? 6 thirds = ? 12 sixths == ? f = ? | = ? | = ? | = ? ll = ? Y = ? 1 d ' ' ' " ... Chapter One. r *«» 'A mixed* number is a whole number and a fraction written together. 3. A proper fraction is a fraction whose numerator is less than its denominator. An improper fraction is a fraction whose numerator is equal to or greater than its denominator. 4. Change each of the following improper fractions to a whole number or to a mixed number : ¥ ¥ V ¥ ¥ i 5. Oral Exercises. How many quarts in a gallon? What part of a gallon is a quart ? \ gallon = how many quarts ? \ = how many fourths ? How many quarts in a peck ? What part of a peck is one quart? One-half peck is how many quarts? One-half = how many eighths ? \ peck is how many quarts ? \ = how many eighths ? \ =how many eighths ? how many eighths? il I 1 si Mixed Numbers. 3 6. Draw a line one foot long. Draw a second line of the same length ; divide it into halves. Divide a third line of the same length into three equal parts. Divide three other lines, one into fourths, one into sixths, and one into twelfths. How many inches in a foot ? What part of a foot is one inch ? J foot = how many inches ? \ — how many twelfths ? 1 = how many twelfths ? f = how many twelfths ? Change \ to twelfths. Change j, f to twelfths. How many twelfths _ 1 ? 2? 3 ? 4? 5? 6? — $"• 3"' 6* ^' 6* 6 ' 2 _ ? 3 _ ? 4 _ ? _ 2 T2"— 6 TJ — f TJ — ^ — ^ 6 _ ? _ ? _ ? 8_?_? 9_? T2— "6"— T — "2 T2"— ~5 — T T2~ — 4~ 10—1 44 = 1=1 = 1= i How many inches in f ft + J ft. + J ft. + 1 ft. + ^ ft. ? How many feet and inches ? How many 12ths in i+i + i+J + yV? Change to a mixed number. Change the fractional part to a different fraction having the same value. What fraction of a dime is 1 cent ? £ dime = how many cents? £ = T V £ dime = how many cents ? £ = T V Change f to tenths. !• t !• Add -i- dime, £ dime, and ^ dime. How many cents? How many tenths = 1 + i + T V ? Can y° u change the answer to a different fraction having the same value ? 7. Oral Problems. 1. I spent 1 of a dollar for a ball and T ^ of a dollar for a bat. What part of a dollar did I spend for both ? 2. What is the cost of a pen-knife at f of a dollar, and a book at i of a dollar ? 3. I need -J of a yard of ribbon for one hat and £ of a yard for another. How much ribbon should I buy ? 4 Chapter One. 4. Sold f of a pound of tea to one customer and £ to another. How much was sold to both ? 5. What quantity of oats should I buy to give J of a peck to one horse and | to another ? 6. If I sell i- of a dozen of oranges to one person and J of a dozen to another person, what part of a dozen do I sell ? 7. f of an hour is how many minutes ? 8. I spent J of an hour reading and ^j- of an hour writ- ing. What part of an hour did I spend at both ? 9. A boy is carrying 6 J pounds of flour, and 6 J pounds of ham. What is the weight of his load ? 10. 18 hours are what part of a day ? ADDITION OF MIXED NUMBERS. 8. In fractions the numbers above the line are called numera- tors ; the numbers below the line are called denominators. The numerator and the denominator are called the terms of a fraction. To add fractions they must have a common denominator. A common denominator is a number that will exactly contain all the denominators. The least common denominator is the least number that will exactly contain all the denominators. 9. Add 12}, 6fc 8J, 15f , |. 24 12} 12 61 16 H 6 15* 20 | 9 43| ff 2f. Arts. 43f. Mixed Numbers. 5 An inspection of the denominators, 2, 3, 4, 6, 8, shows that 24 is the smallest number that will contain each without remainder. This is the least common denominator. Instead of writing the least common denominator 24, with each fraction, we may place it above, and write only the new numerators. } = if, | = ££, i = fo etc. Write 12, 16, 6, 20, 9. The sum of these numerators, 63, is written over the denominator 24, making the sum of the fraction ff. This improper fraction is reduced to 2|$, and the fractional part is reduced to f. f is placed under the fractions to be added, and 2 is carried to the whole numbers, making 43. Add the fractions and unite their sum with the sum of the The fractional parts of answers should be reduced to lowest terms. 10. Written Exercises. Add: 1. 23* 2. 73* 3. 93| 4. 11$ 5. 18* 63* H 2* 3* 7* n 39& 7±A 20A 9A 3A 16* 6* 5+ i 6. 12* 7. 19* 8. 73} 9. 5** io. loo* 3A n 98* 38* 75* 27f 34£ i 23* 9* Ji- _± 33* 17* 49* ll. 33| 12. 6^ 13. 103* 14. 218f 15. 444* m 18* 84* 301* 518f 2*A 32* 25* 18* 37* 69A 94* H 24| 95| 6 Chapter One. 11. Written Problems. 1. A merchant sold 17f yards of muslin, 14J- yards of silk, and as many yards of calico as of the other two together. How many yards did he sell in all? 2. A boy has to walk from his home to a house If miles east of his home, and from there to a place 2£ miles west of his home. How far has he to walk ? 3. From a piece of cloth 17-J- yards, 5f yards, and 4f yards were sold. How many yards were sold ? 4. A man walked 12^ miles Tuesday, 16f miles Wed- nesday, 22 ^ miles Thursday. How far did he walk in 3 days? 5. A farmer owned 3 fields containing, the first 21| acres, the second 27f acres, and the third 28^ acres. How many acres were there in all ? 6. A man bought 3 loads of wood containing respec- tively 1J, cords, If cords, and If cords. How many cords of wood did he buy ? 7. A man has 10^ acres of wheat, 6f acres of corn, 20f acres of barley, 16 § acres of rye. How many acres of grain has he? 8. William lives 24£ rods from school, James 6^ rods farther than William, and Charles 10^f rods farther than James. How far does Charles live from school ? 9. Henry weighs 58 T 3 b r pounds, Peter 65} pounds, and John 67f pounds, and their father as much as all three of them. How much does their father weigh ? 10. A dealer mixed 2-J- pounds of black tea costing 32 cents per pound with 1£ pounds of green tea costing 40 cents per pound. How much per pound does the mixed tea cost him ? Mixed Numbers. 7 SUBTRACTION OF MIXED NUMBERS. 12. Preliminary Exercises. l-i=? li-i=? 10-*=? 10J-i=? 10i-li=? In subtraction of mixed numbers, as in addition, the fractions must have a common denominator. Subtract : 1. left 2. 49$$ 3. 38$f 4. i»A 5. 27A 13A 37$$ 29$$ "ft 16ft 6. 28^ 7. 47$ 8. 36i$ 9. 25$$ 10. 32$$ 13* 29$ 1»A 19$$ ISA 13. From 197$ take 68$. 15 Reduce the fractions to the least common denominator 197| 9 15, as in addition of fractions. {% being greater than 68$ 10 ■fs, we change 197-& to 196 + 1£, or 196f = i|. 196-68 = 128. Ans. 128}|. *• tt-tt 128$* 14 T5 Reduce the fractions to the least common denominator, and subtract the fractions and the integers separately. 14. "Written Exercises. 1. 36| 2. 63L 3. 27f 4. 05f 5. 105^ -*i -9 T V -17i -25f -8J 6. 120$ 7. 39$ 8. 13$ 9. 99$ 10. 67$ -84$ -38$ -7ft -21$ • -59$ 11. lOOJy 12. 25A 13. 93A 14. 101$$ 15. 12$ 76$ 5$ 24$ 98$ 4$ 16. 21. 26. Chapter One. 23£ 17. 9A ft 18. 133} 27* 19. 16^ 3* 20. 37J 29J 52| 22. 64£ 18£ 23. 125-ft lOOf 24. 47i 8* 25. 72 T V 50£ 31f 27. 27A 63^ 44j. 28. 3^ 29. 25f Hi 30. 102/j 86J 15. Oral Problems. 1. A man had $6^, and he spent $ 3 J. How much money had he left ? 2. Take $ 8 \ from $ 12f. How many quarters of a dollar are there in the remainder? 3. One-half of our books are in the case ; we have in all 184 books ; one-half of the remainder are on the table. How many are on the table ? 4. If 6 apples cost 14 cents, what will 3 cost ? 5. How many hours from 10 a.m. to 10 p.m. ? 6. A man had 1000 acres of land and sold 996 J acres. How many acres had he left ? 7. If a man earns $ 14£ in a week, and spends $ 8f , how much does he save ? 8. Bought sugar for 5J cents a pound, and sold it for 6J cents a pound. What was the gain on 200 pounds ? 9. What will 12f pounds of beef cost at 16 cents a pound? 10. If a girl studies 5\ hours in school, and 1\ hours at home each day, how many hours does she study in a week of five days ? Mixed Numbers. 9 16. Written Problems. 1. The weight of a tub of butter, including the weight of the tub, is 48J pounds. The tub weighs 9£ lb. What is the butter worth at 24 cents per pound ? 2. A farmer had 7 bushels of potatoes. He used 2 bushels and 3 pecks for seed. What would the remainder be worth at 20 cents per peck ? 3. How much heavier is a cheese weighing 40J pounds than one which weighs 26f pounds ? 4. A farmer having 217 bushels of corn sold 95 }{ bushels j how many bushels had he left? 5. A milliner gained 1-J dollars by selling a hat for 6£ dollars ; what did it cost her ? 6. From a cask of oil containing 43f gallons, 17| gallons were drawn ; how many gallons remained ? 7. A man having 25J dollars paid 6J dollars for coal, 2\ dollars for dry goods, and £ of a dollar for a pound of tea ; how much had he left ? 8. A butcher buys an ox weighing alive 1200 pounds, at 6 cents per pound. When killed and dressed, its weight is f of the live weight. What is the butcher's profit, if he sells the meat at an average of 15 cents per pound ? 9. A farmer sold 36^ dozen eggs to one storekeeper, 5J dozen to another, 17f dozen to a third, 8f dozen to a fourth, and 11 T 7 2- dozen to a fifth. How much did he receive for them at 12 cents per dozen ? 10. A teacher's salary per month is 135^ dollars, and his expenses average 51 J dollars : how much does he save per month ? 11. A man gave \ of his money to his wife and i of it to his daughter. He divided the remainder equally among his three sons, each of whom received $1000. How much money had he? io Chapter One. MULTIPLICATION OF MIXED NUMBERS. 17. Preliminary Exercises. i + i + } = ? 3timesJ = ? ixS = ? 6 times \ = ? 3 times £ = ? |x3 = ? | X 9 = ? |xl5 = ? |xl7 = ? | X 7 = ? f x 20 = ? £ x 12 = ? £ X 5 = ? fxl3 = ? |xlO = ? 18. Multiplication of a mixed number by an integer. Find the product of 235f by 39. 235f Multiply 3 by 39; divide the result by 4: the 39 quotient, 29£, is 39 times f . Write the next partial 4 )117 product, 235 x 9 ; then the product of 135 by 3 tens. 29J The sum of the three partial products gives the 2115 result, 9 194 J. 705 19. Oral Exercises. 9194J Ans 1. 1| X 9 = ? 3. 3|x5 = ? 5. 5fxl2 = ? 2. 2|x7=? 4. 4| x 8 = ? 6. 6^x10 = ? 20. Written Exercises. 1. 215§xl7 = ? 3. 417^x20 = ? 5. 619^x19 = ? 2. 316fxl5 = ? 4. 518£xl3=? 6. 720 T \x23 = ? 7. 163| 9. X75 509£ X213 11. 6089f X1004 8. 103| 10. Xl7 308| X156 12. 1607f X2340 Mixed Numbers. n 21. Multiplication of an integer by a mixed number. Multiply 276 by 280|. 276 280# Multiply 276 by the numerator, 3; divide the Q\eo8 product by the denominator, 8 ; the quotient, 103£, is ^.n 4 ^ the product of 276 by f . Multiply 276 by 8 tens and by 2 hundreds, etc. 2208 552 77383^ Ans. To multiply a whole number by a fraction, place the product of the numerator by the whole number over the denominator, and reduce, if possible. 22. Written Exercises. 1. 13x7| =? 4. 17x10^ = ? 7. 102x22f = ? 2. 19x8^ = ? 5. 21xll| =? 8. 204x34f = ? 6. 27 x 12f m ? 9. 468 x 56f = ? 12. 4060 14. 3579 T V X 2050| x 4300 3. 23 x 9^- = 9 10. 387 x400f 11. 698 Xl35f 13. 3050 15. 4987^- X 2060f x 2469 23. Oral Problems. 1. How many ounces in 6% pounds ? 2. I sold 3^ yards of silk and 2f yards of velvet. How many yards in all did I sell ? 3. From 60 take 24. Find \ of the remainder. 4. | of 100 rods = ? 6. | of 81 yards = ? 5. (fof60)-9 = ? 7. f of 56 pounds = ? 12 Chapter One. 8. | of a yard and 12 inches are how many inches ? 9. If one-half a pound of soap costs 10 cents, what will three pounds cost ? 10. John is going a journey of 100 miles ; if he travels | of the distance in the cars and the rest in a coach, how many miles will he travel in the coach ? 11. How many times must I fill my glass, which holds £ a pint, to fill my pitcher, which holds a gallon ? 12. If a boy is in school h\ hours a day, how many hours is he in school in 200 days ? 24. Written Problems. 1. What is meant by f of any number or thing ? Make a drawing to show what you mean. 2. What is the cost of 15^- acres of land at $45 an acre ? 3. Reduce £, f, §, and ^ to fractions having a common denominator. 4. What is the cost of a side of beef containing 252 pounds at 9J cents a pound ? 5. A hotel uses 18f pounds of beef in a day. What will be the weekly bill at 22 cents a pound ? 6. A man walks 3^ miles in one hour. How far can he walk in 9 hours ? 7. From a piece of muslin containing 37£ yards, three pieces each measuring 7-J- yards were sold. How much remained in the piece ? 8. At $ 7.86 a barrel, what will 18| barrels of flour cost ? 9. Bought 6 bushels of apples at 62 \ cents a bushel, and sold them at 12£ cents a half-peck. What was the gain? 10. In a school containing 945 pupils ^ of the number were boys ; how many boys in the school ? 11. What is the cost of 15 acres of land at $ 45£ an acre ? Mixed Numbers. 13 12. If a quart of cream is worth 22 cents, what are two gallons worth ? 13. At 9 cents a quart, what is the cost of 2\ gallons of vinegar ? 14. What is the total quantity of molasses in 4 casks containing, respectively, 40 J, 25f 27-^-, and 55| gallons ? 15. The Post-office Department bought 6670 pounds of twine at 19 J cents a pound ; 372 pounds of sponge at 65£ cents a pound, and 40£ dozen of ink at $2 a dozen. What was the total cost of the purchase ? DIVISION OF MIXED NUMBERS. 25. Preliminary Exercises. t , How many times is \ of a dollar contained in $ 1 ? How many times is 1 of a pint contained in 1 pint ? \ of a gal- lon in 1 gallon ? How many times is ^ of a dollar contained in $ 2 ? In $ 3 ? In $5? How many times is -J- of a dollar contained in $1.50? In $2.50? In $3.50? In $4.50? How many times is 1 half contained in 3 halves ? In 5 halves ? In 7 halves ? In 9 halves ? 3-1-1=? 5^_\—9 l-±-l = ? 5.-^1 = ? 2-Y* 2 ' 2 ' 2 ' 2 * T * ^ ' How many times is f contained in f ? In f ? In -^ ? In^f? Divide 1| by If 4£ by If 7| by If 10J by If Divide 3 by If 6 by If 9 by If 12 by If 15 by If Divide 5 by If 6Jbylf 10 by If lljbylf 15 by If Divide i by f. £by|. 1} by f . 1$ by f. 2J by $ 3 by J. 3fby{. 14 Chapter One. 26. Written Exercises. 1. Divide 250 by 12$. 250 = 500 halves. 12$ = 25 halves. 600 halves -=- 25 halves = 500 ^ 25 = 20, Ans. Proof : 20 x 12$ = 250. 2. Divide 62\ by 25. 62$ = 125 halves. 25 = 50 halves. 125 halves -r- 50 halves = 125 -r- 50 = 2£f = 2$, Ans. Proof : 25 x 2$ = 62$. 3. Divide 1387$ by 18}. Ans. 74 18| = 75 fourths. 75)5550 Change 1387 1 to fourths by multiplying by 4. ^25 1387$ x 4 = 5550 ; that is, 1387$ = 5550 fourths. 300 75 fourths is contained in 5550 fourths 74 times. 300 Reduce the dividend and the divisor to improper fractions of the same denominator, and divide the numerator of the divi- dend by the numerator of the divisor. Prove the correctness of the answer by multiplying the quotient by the divisor. 27. Written Exercises. Div 1. ide: 60+ \ 11. 75 + 12$- 21. 62| + 12$. 2. 60 + 1* 12. 150 + 12$- 22. 187$ + 12^ 3. 60+ i 13. 75+ 6J 23. 81 J + 6J 4. 60 + 1* 14. 150+ 6J 24. 193}+ 6J 5. 60+ \ 15. 62 + 15$- 25. 77$- + 15$ 6. 60 + If 16. 105 + 17$. 26. 192^ + 17$ 7. 60+ * 17. 69+ 5} 27. 97}+ 5} 8. 60 + 2* 18. 93+ 7} 28. 193}+ 7} 9. 60+ } 19. 100 + 33$ 29. 166$ + 33$ 10. 60 + 3J 20. 150 + 16f 30. 133$ + 16 $ Mixed Numbers. 15 31. 601-^2 34. 87i-f-6J 37. 60 -- 3f 32. 60 33. 15f 71 35. 621 --6J 38. 241 If 36. 60f-=-3 39. 87£ If 28. Oral Problems. 1. I paid 18 cents for 11 pounds of lard. What is the price per pound ? 36 cents for 3 pounds. 2. At f dollar per yard, how many yards of silk can be bought for $ 9 ? 36 quarter dollars -=- 3 quarter dollars. 3. If one fish cost 25 cents, how much would 2\ fish cost? 4. A man bought 30 apples at the rate of 3 for 5 cents. How much did he give for them ? 5. If I pay 6 cents for a dozen apples, how much does each apple cost ? 6. How many times is 41 contained in 27 ? 7. If 21 bushels of oats will keep a horse one week, how long will 18 bushels keep him ? 8. If $ 97 is \ of a sum of money, what is that sum ? 9. What is the cost of 12 doz. eggs at the rate of 2 eggs for 3 cents ? 10. If 3 boys can cut a cord of wood in 8 hours, how long will it take 4 boys to cut a cord ? 11. If i of a melon costs 15 cents, what will two melons cost at the same rate ? 12. It takes 2\ yards of cloth for a pair of trousers. How many pairs can be made from 30 yards of cloth ? 13. Paid $ 12.90 for 3 pieces of lace. How much did each cost ? 14. If 3 straw hats cost 63 cents, what will be the cost of 5? 1 6 Chapter One. 29. Written Problems, 1. A farmer distributed 15 bushels of corn among several persons, giving them If bushels apiece; among how many- persons did he divide it ? 2. A man bequeathed to his son $ 3500, which was -f- of what he left his wife. How much did he leave his wife ? Suggestion. — } of wife's share = $ 3500. Multiplying by 7 : 5 times wife's share = $24,500. 3. If f of a farm is valued at $ 1728, what is the value of the whole ? 4. A man walks 4f miles in one hour, how far can he walk in 9 hours ? 5. At | of a cent a foot, how many feet of wire can be bought for $1.26? 6. The sum of 69f dollars was divided equally among 5 men ; what was each one's share ? 7. At | dollars per yard, how many yards of cloth can be purchased for $98? 8. In how many days can a horse eat 66 bushels of oats if he eats f of a bushel a day ? 9. A man bought chairs at 4f dollars apiece for 114 dollars, and then sold them at 6 J dollars apiece ; how much did he gain? 10. A man sold 9f bushels of seed for $61.60; find the price per bushel. 11. What part of 24 is 3 ? What part of 24J is 8} ? 12. What would be the cost of 24^ pounds of beans at the rate of 11 cents for 3£ pounds ? Review of Notation and Numeration. 17 30. Notation and Numeration. The largest number that can be written with six figures is 999,999. 1,000,000, is called one million. Write in figures two million. Three million. Four million. Six million. Eight million. Ten million. 31. Bead the following : 1. 1,234,567 6. 11,034,065 11. 30,100,021 2. 3,000,560 7. 14,602,500 12. 35,000,600 3. 5,009,008 8. 17,386,925 13. 401,023,160 4. 7,090,070 9. 20,007,316 14. 760,030,020 5. 9,843,000 10. 25,000,005 15. 980,750,000 32. Write in figures : 1. Seventy-eight million, one hundred eight thousand, ninety-six. 2. Three million, eight. 3. Fourteen million, seven thousand, five. 4. Nine hundred eighty-seven thousand, six hundred fifty-four. 5. Twenty million, thirty thousand, forty. 6. Three hundred seven million, nine hundred four thou- sand, six. 7. Nine hundred ninety-nine million, nine hundred ninety-nine thousand, nine hundred ninety-nine. 8. Four hundred seventy-six million, three hundred thousand. 9. Thirty-four thousand, eighteen. 10. Sixty-four million, thirty-two thousand, sixteen. 11. Add the foregoing. 1 8 Chapter One. REVIEW OF FUNDAMENTAL OPERATIONS. Practice in the fundamental operations should not be neglected. Business men complain that elementary and high school graduates cannot add. Read the following numbers. Add each column. 1. 27,083,549 2. 508,900,007 3. 2 43,576,908 3,006,005 4,629,880 5,987,600 20,080,070 25,936,097 380,070 1,647,893 134,870,603 68,000 206,045 59,009,300 593,056 73,000 7,000,004 2,384,672 180,059 686,909 59,876,004 4. 9,256,874 5. 348 6. 7,293 863,052 2,967 82,538 24,635,998 36,847 786,324 7,007,007 243,837 94,649 6,875,634 183,634 256,834 3,987,456 986,246 3,983,387 35,068 8,216 54,619 705 586,237 760,888 33. Oral Exercises. Give answers : 1. 1200x6 6. 1300x9 11. 2100x4 16. 1400x8 2. 1800x4 7. 2300x3 12. 1400x6 17. 2400 x 4 3. 2500x3 8. 3200x2 13. 4100x2 18. 1300 x 7 4. 1700x5 9. 1500x4 14. 1600x5 19. 1200 x 9 5. 1400x7 10. 1200x8 15. 2200x3 20. 6300x2 Review of Fundamental Operations. 19 34. Written Exercises. Multiply: 1. 9,207x3014 2. 5,482 x 798f 3. 5,290 x 6075 4. 9,204 x 678J 5. 75,074 x 395 6. 68,431 x 924| 7. 95 x 95 x 95 8. 185 x 19 x 78 9. 87£x 23 x 36 10. 706 x 304x509 11. 48Jx 32 x 74 12. 538 x 247 x 125 35. Oral Exercise «. Divide : 1. 960-240 6. 8400-^2100 11. 10800-1200 2. 780 h- 260 7. 8600-4300 12. 10400 -j- 1300 3. 960 -5- 480 8. 8800-2200 13. 6000 -r- 1500 4. 720-180 9. 9600-3200 14. 5700-1900 5. 2170-310 10. 9900 -;- 3300 15. 12000 -h 2400 The foregoing exercises are given as a preparation for the long division drill that follows. Each of the above set has an exact quo- tient, easily determined at sight. The object of the following set is to drill pupils to obtain rapidly the correct quotient figure in a long division example. A pupil giving 4 as the answer to No. 1 should be asked to give the product of 241 by 4. 36. Long division drill. (Omit remainders.) 1. 960-241 2. 779^-260 3. 959-480 4. 720-181 5. 1160 -r- 130 6. 8,400-2110 7. 8,500-4300 8. 8,800-2199 9. 9,599-3199 10. 10,000 -j- 3330 11. 10,800-1205 12. 10,300-1300 13. 6,100-^1550 14. 5,700 - 1899 15. 12,020-5-2410 28. 14f-8i-3f + 4J 29. (8ft + 6|)- •(»A- <® Fractions. 67 30. 4f x 16 x 8£ 31. (M**k}Mm-H+m 32. (8i + 4J)-(2i + li) 33. (3^x36)x8f 34. 4| + 3i-6f + 17i-9f 129. Oral Problems. 1. A person travelling from New York to Albany (140 miles apart) has gone 102J miles. How much farther has he to go ? 2. There are 196 pounds of flour in a barrel. How many pounds in J barrel ? 3. How many fourths in 24 J ? 4. Eeduce f$ to lowest terms. 5. Change ±$Q- to a mixed number. 6. Add i, ^, and J. 7. From a chest of tea containing 45 J pounds, 14| pounds are sold. How many pounds remain ? 8. From ^ of a dollar take 10| cents. 9. How many cents in ^ + ^ -f- y% of a dollar? 10. A farmer has 60| acres of pasture and 20| acres of woodland. How many acres in both ? 11. Considering the circumference of a circle as 3^ times its diameter, find the circumference of a circle whose diam- eter is 8 feet. 12. Mary is 12^ years old; Jane is 3fJ- years older* How old is Jane in years and months ? 13. In a year and a half William will be 7 years 2 months old. How old is he now ? 68 Chapter Two. 14. What number multiplied by 3 equals 231 ? 15. What number between 7 and 12 is a prime number ? 16. A boy received 9 marks in arithmetic, 8 in penman- ship, and 7 in reading. What was his average mark ? 17. -f of a class consists of boys. How many girls in the class, if it contains 49 pupils ? 18. When July 1 falls upon Tuesday, what will be the date of the third Tuesday of July ? 19. If July 1 falls upon Thursday, upon what day will the first of August fall ? 20. A man bought 20|- pounds of sugar; he sold 10| pounds at one time and 6J pounds at another. How much had he left ? 21. If 3 quarts 1 pint of oil cost 7 cents, what will 1 gal- lon 1 quart cost ? 22. How much will have to be paid for 7 cows at $50 each, and 4 horses at $ 150 each ? 23. f = how many hundredths? 24. What are the two factors of 87 ? 25. Find the G. C. D. of 36 and 54. 26. If eggs are sold at the rate of 21 for 25 cents, how much will be paid for 5 \ dozen ? Suggestion. — Every member of the class should be required to solve one of the foregoing examples as a sight problem, first reading it from the book, and then giving the answer. No time should be wasted in "analyzing" the problems, unless some pupil desires the explana- tion of one that he does not understand. At another time, the teacher should read, say, five or ten problems, requiring the answer to each to be written, at a given signal, and the pencil laid down before the next is read. No alteration of an answer should be permitted. Fractions. 69 130. Written Problems. 1. A horse travelled 48^- miles in one day, 56| the next, 40i| the third, and 45f-J the fourth. How far did he travel in all ? 2. To the sum of 6£ and 19| add their difference. 3. From a bin containing 25f bushels of grain there were taken out 5f bushels at one time and 6J at another. How much remained ? 4. A merchant sold 4 pieces of cloth containing 21\ yards, 26f yards, 29f yards, and 28±- yards, respectively. How much did he receive for the cloth at 96 cents per yard ? 5. Keduce ||-| to lowest terms. 6. A man has 8^- bushels of peanuts. He puts them into bags holding -^ bushel. How many bags does he fill ? 7. A 160-acre farm consists of five fields ; the first contains 17-f acres, the second 29£ acres, the third 35^j- acres, the fourth 22-fe acres. How many acres are there in the fifth field ? 8. Prom a piece of silk that contained 28£ yards, there were sold 2\ yards, 6£ yards, and 13| yards. Find the value of the remainder at $1.20 per yard. 9. Three pieces of cloth bought at $2 per yard cost $150. The first piece measures 23£ yards, the second measures 30f yards. How many yards in the third piece ? 10. What part of a person's income remains after he spends J, -^, and \ of it? 11. A boy loses \ of his marbles, and he gives away \ of them. If he has 17 marbles left, how many had he at first ? 12. A dealer sells If gross, 3J gross, and 8| gross of lead pencils at 36 cents per dozen. How much does he receive for all ? 1 gross = 12 dozen. 70 Chapter Two. 13. There are four towns, A, B, C, and D, on a certain railroad running east and west. A is 41^- miles west of C ; D is 39J miles east of B ; B is 22£ miles west of C. How many miles from A to D ? Make a diagram. CANCELLATION. 131. Preliminary Exercises. 1. Divide 64 by 16. The quotient is 4. 2. Divide \ of 64 by £ of 16 ; i.e. 32 -*- 8. 3. Divide \ of 64 by J of 16 ; i.e. 16 -f- 4. 4. Divide \ of 64 by £ of 16 ; i.e. 8 -h 2. In each case the quotient is 4. In example 2 we took out of the dividend 64 the factor 2, making the new dividend 32 ; and we took out of 16 the same factor, making the new divisor 8. In example 3 we took what factor out of the divisor and the divi- dend ? What common factor was taken out in example 4? Rejecting the same factor from the divisor and the dividend does not change the quotient. In reducing -fj to J what factor common to the numerator and the denominator of the first fraction is rejected ? Is the value of the first fraction altered by this rejection? Cancellation is the striking out of common factors from the divisor and the dividend. 132. Oral Exercises. 36 x!4 42 x23 67 x 36 83 x 36 9 21 18 ' ' 12 2 -f x16 6 -2^ x46 10 -i x82 14 -if x48 3 ' 12x i 7 - 32x I "' 4X i 15 ' 15X | 25x18 33x12 89 x 13 44x17 36 ' 99 26 34 Fractions. 71 RATIO. 133. Preliminary Exercises. 1. If oranges are worth 28 cents a dozen, what will be the cost of 3 oranges ? 2. What part of a dozen is 3 ? 3. What is the ratio of 3 to 12 ? Ratio is the relation between two like numbers. It is found by dividing the first by the second. 4. What is the ratio of 12 to 16 ? 5. If 16 apples cost a certain sum, what part of this sum should be paid for a dozen apples ? 134. Written Exercise. 1. If 17 horses cost $4000, what will be the cost of 51 horses at the same price for each ? Since the ratio between 51 and 17 is f^ or 3, 51 horses will cost 3 times §4000, or $12,000. 2. If 15 eggs cost 25 cents, what will 10 dozen cost? 10 x 12 The ratio of 10 dozen eggs to 15 eggs is — - — • 15 Multiply 25 cents by - 10 x 12 . 15 In this case, 15 is not contained in any number above the line. We divide 15 and 10 by 5, cancel- 2 4 ing them and writing quotients 3 and 2 alongside. 25 X %$ X \% 3 is contained in 12 4 times ; so we cancel 3 and 12. J.fi Our answer now is 25 cents x 2 x 4 = 200 cents, p or $2. 3. Eighteen men can do a piece of work in 26 days. How long will it take 13 men to do the same work? Thirteen men will do the work in \\ of the time required by 18 men. 72 Chapter Two. 4. Seventeen barrels of flour, 196 pounds each, were put into bags holding 49 pounds each. How many bags of flour were put up? 5. At the rate of 23 cents for 7 pounds, how much would be paid for 91 pounds of flour? 6. A bank pays $ 4 interest a year on every $ 100. How much interest will be paid for 3 years on $650? 7. At $ 7.50 per thousand for bricks, what must I pay for 63,200 bricks? 8. If flour is $ 6 per barrel (196 lb.), what must be paid for a 49-pound bag? 9. A grocer buys 84 dozen eggs, and sells them at the rate of 21 eggs for 25 cents. What does he receive for them? 10. A miller buys 9840 pounds of wheat at 90 cents per bushel of 60 pounds. How much does he pay for it ? 11. What will be the cost of 64 sheep, if 18 cost $ 198 ? 12. If 18 men can do a piece of work in 42 days, how long will it take 21 men to do the same work? 13. What will be the cost of 66 dozen pens at 42 cents per gross of 12 dozen? 14. A certain quantity of hay feeds 15 horses 56 days. How long will it feed 14 horses ? 15. A merchant bought 9 pieces of cloth, each containing 24 yards, for $ 189. What was the price per yard ? MULTIPLICATION OF FRACTIONS 135. Preliminary Exercises. What is i of 2 fifths ? Of 4 sevenths ? Of 6 elevenths ? What is \ of i? Of£? Of J? Of J? Show by diagram What is \ of |? Off? Off? Off? What is \ of f? fof£? fof£? Fractions. 73 What is -§- of I? I off? foff? What is -I of i? ioff? fofj? foff? What is the half of 1£? 0f2i? 0f3|? Of 4^? What is one-third of 1£ ? J of 1\ ? £ of 2\ ? f of 2J ? 136. "Written Exercises. 1. Multiply £ by f. This means to find # of f . Since * of * = A» i of * = A. and } of f = &, or | x f = &. One fraction is multiplied by another by placing the product of the numerators over the product of the denominators in the form of a fraction. Note. — Cancel when possible. 2. Multiply I by A- i°f A = A £<>f A = 2timesA = f 3 Cancel 2 and 10, writing 5 under 10. Cancel % ^ ft _ 3 3 and 9, writing 3 above 9. £ 20 5 Show by a diagram that 2 times ^ is \. 5 3. Multiply 12i by 3^. Reduce the mixed numbers to improper fractions. 17 7 g2 40 = 119 == 3 4. Multiply 117 by 3|. The multiplication of an integer by a mixed number, or of a mixed number by an integer, can 13 be considered as multiplication of fractions, the 2ML v _ — 377 integer being written as an improper fraction with 1 ^ 1 for the denominator. 74 Chapter Two. 137. Multiply: 1. | by 96 16. &x$% 2. 128 by | 17. 3fbyl2£ 3. * by | 18. $ x 4« ibyf 19. fbyfbyH 5. * by* 20. fj of |f of 4. 6. 3^ by 72 21. |} x f X * 7. 24fbyl8 22. ft of ft of ff 8. 69fby32 23. J of 65f 9 10 11. 2£by3f 26. 4^x5^ 12 13 111^ by 28 24. fof55f 67by^ 25. 6Jx7| 14. 15. AX2J- 27. § of 4^x3* 17iby6f 28. |of3|x4 I V 6*xf 29. Hx2Jx3J 4Jby8f 30. 2£x2Jx2J 138. Perform the indicated operations : Note. — \ of 3 J is the same as \ x 3 J, or 3 J x $. 1. J of (3H-6J) 6. (8} x 21) -(* of 15© 2. <3*-2»X| 7. 5i + 6J + 7J 3. iof(5i-3f) 8. 18f-8|-7J 4. (24J + 16i)H-8 9. f off of (3* + If) 6. (3i+2*)x(3i- •2fi 10. (l 8i -6f) +11 139. Oral Exercises. 1. Sold a house lot for $30, which was J of what it cost me. What was the cost of the lot ? 2. A man can mow 6 J acres of grass in a day. How much can he mow in 6 days ? Fractions. 75 3. A man bought 15 bushels of corn for 1\ dollars. How much did a bushel cost ? 4. A boy is 18 years old and his age is f of the age of his father. How old is his father ? 5. Cloth is worth fo of a dollar a yard. What is f of a yard worth ? 6. At the rate of 5 cents for \ of a pie, for how many pies will a man receive $ 1.60 ? 7. What would |- of a yard of carpet cost at f of a dollar a yard ? 8. I had ^2 °f a pound of candy and gave away f of it. What part of a pound did I give away ? 9. What will 15 yards of ribbon cost at 6§ cents a yard ? 10. What will 2f gallons of ice-cream cost at If dollars a gallon ? 140. "Written Exercises. 1. A man worked 6 days at 2} dollars per day, his son 5 days at If dollars, his daughter 4 days at £ of a dollar. What were their total earnings ? 2. A merchant bought a piece of cloth for 28| dollars and was obliged to sell it for -| of what it cost him. How much did he lose ? 3. A hotel in one month used 31 pounds of coffee and 7f times as much sugar. How much sugar was used ? 4. A man gave 124 T 5 g- acres of land to his two sons, giving f of it to the elder and ■§■ to the younger. How many acres did each receive? 5. If it requires 21| days for a man to dig a ditch, what part can he dig in 15 days ? 7 6 Chapter Two. 6. If a bird can fly lOf miles in f of an hour, how far can it fly in 2£ hours ? 7. What would be the cost of a side of veal containing 52 pounds at 9 \ cents a pound ? 8. What will 16 pairs of shoes cost at % 3} a pair ? 9. A man who owed $ 7825 failed and could pay only | of his debts. How much could he pay ? 10. I bought a house and lot and made a payment of % 4500, which was f of the cost. What was the cost of the property ? DIVISION OF FRACTIONS. 141. Preliminary Exercises. 1. If 3 yards of calico cost 18 cents, what is the price per yard ? 18 j* -T- 3, or \ of 18/?. The latter may be written 18 j* x \. 2. If \\ yards of dress goods cost 18^, what is the price Per yard? i 8 ^ H , or 18^|. To divide 18 by f , we can change 18 to halves and proceed as fol- lows : *£■ + f = 36 + 3. The following are the steps : 18 is multiplied by 2, and the product 18 v 2 is divided by 3, or ° * , which is the same as 18 x f . o That is, 18 + | = 18 X f. 3. If 3 yards of dress goods are required to make a waist, how many waists can be made out of 18 yards ? The number of waists = 18 -r- 3 = \ of 18 = 18 x \. That is, 18 -?- 1 = 18 x \. 4. If an apron requires \\ yards of material, how many aprons can be made out of 18 yards ? The number of aprons = 18 -*• \\ = 18 -*- \ = 18 x f. Fractions. 77 5. If it takes three-quarters of a pound of flour to make a loaf of bread, how many loaves can be made with 18 pounds of flour? The number of loaves = 18 -j- f = 18 x $ . 6. At three-quarters of a dollar each, how many dolls can be bought for a dollar and a half ? To divide by $ (examples 1 and 3), we multiply by $. To divide by f (examples 2 and 4), we multiply by f. To divide by £ (examples 5 and 6), we multiply by f. To divide by a fraction, multiply by the divisor inverted. 7. Divide 8 by |. 8-=-§ = 8xf = 10, Ans. 8. Divide f by 10. 9. Divide 6f by 9. 142. Divide: 1. |+4 4. ^-A 7. A-f-H 9. t+3| 2. f + 10 5. H-t\ 8. 3f + * 10. i-| 3. lf+5 6. A+A 143. "Written Exercises. 1. Divide A by & 3 5 16 * 20 J0 2 4 * 4 2. Divide 15^ by 13. Changing the mixed number to an improper fraction, we have, 13 7« 8 Chapter Two. Divide : 3- A+A 8. A^ 13. 8A + 3J 4. 5-f-lf 9- tt + *A 14. 9* + 3* 5. 8$ -5- 11 io. f+* 15. 18J + 1H 6. 4^-17 ii. A^-l 16. 2H+6# 7. 24J-20 12. A+A Note. — The pupil should prove his answers to each of the foregoing examples by multiplying the quotient by the divisor. If his answer is correct, this product will equal the dividend. 144. Perform operations indicated : 17. (3fx4i)-10J 24. (tfx«) + (4f x6» 18. (13f-7f)xf 25. 34f-17f + 20« 19. (20 x })-*-! 26. 18| + 24^-36iJ 20. (20 + f)x| 5|x9x7| 21. 20 + (|xf) W ' 4f xf 22. (20-*-$)-s-f 51 x 73 x 31, x 6 ^ 23. (14 j x 7) - (9 x 10 1) 2fx 4^x31 145. Oral Problems. Give analysis of each : 1. If base-balls are worth f of a dollar each, what will be the cost of 16 base-balls ? Note. — The pupil is frequently at a loss to determine whether a given problem in fractions involves multiplication or division. In such a case, he should substitute for the fraction a whole number to ascertain the proper operation. While in example 1 a pupil would analyze without hesitation : " If base-balls are worth $ | each, 16 balls would cost 16 times $£," he might stumble at No. 2. By read- ing the problem, "Paid a certain sum for base-balls at $3 each," he would see that the number of balls is ascertained by division. His analysis would then be, "If base-balls are $f each, I can buy as Fractions. 79 many balls as there are $£ in $ 12." The work would be 12 -s-f = 12 x f . He could complete the solution by finding $ of 12, taking $ of 12 as 4, etc. Another method of solving this problem mentally, is to change the price to a whole number and to make a corresponding change in the cost. "Paid 4 times $12 for base-balls at 4 times $ J each ; i.e. % 48 for balls at $ 3 each." 2. Paid $ 12 for base-balls, at J of a dollar each. How many were bought ? 3. What is the cost of 2 feet of ribbon at 30 cents per yard? 4. Find how much a yard of ribbon is worth, if -| yard costs 20 cents. 5. If it takes f yard of material to make a child's waist, how many can be made from a piece containing 24 yards ? 6. If 18 jackets require 24 yards of cloth, how much is needed for 1 jacket ? 7. A man had 60 acres of land. How many acres had he left after selling J- of his land ? 8. After spending £ of his money, a person had $26 remaining. How much money had he at first ? 9. When tea is $ .50 per pound, how much can be bought for $ .75 ? 10. If tea is worth f of a dollar per pound, how much can be bought for i of a dollar ? 11. When silk is selling at $ .75 per yard, how much can be bought for one-fourth of a dollar ? 12. Find the cost of a gallon of milk at the rate of 9 cents for 3 pints. 13. | of a gallon of milk costs 9 cents. What is the price per gallon ? 14. f of what number is 12 ? 15. 1 yard and 1 foot of wire cost 16 cents. How mucb must be paid for a yard ? 8o Chapter Two. 146. Written Problems. 1. How much does a man earn in a day if he earns 45J dollars in a month of 26 working days ? 2. When flour is 5 \ dollars per barrel, how many barrels can be bought for 294 dollars ? 3. If coffee is 37£ cents per pound, how many pounds can be bought for 60 dollars ? 4. A man divided 16 dollars among some boys, giving to each If dollars. How many boys received a share ? 5. Paid 38^ dollars for 6 J cords of wood. What was the price per cord ? 6. How many steps will it take to walk 2640 feet, each step being 2 J feet in length ? 7. A man put 40^ bushels of barley into bags holding 1-| bushels. How many bags were required ? 8. In 2 J acres of land, how many building lots of f of an acre ? 9. If | of a farm is worth $ 8000, what is { of it worth? 10. The product of two factors is 9^ ; one factor is 3£. What is the other ? SPECIAL DRILLS — REVIEW. 147. Give sums at sight: 1. 59 + 75 = 59 + 70 + 5 = 2. 48 + 63 • 5. 88 + 22 8. 66 + 56 3. 69 + 47 6. 94 + 38 9. 29 + 94 4. 67 + 83 7. 61+39 10. 65 + 86 11. 560 + 390 = 560 + 300 + 90 = 12. 270 + 280 14. 430+480 16. 420 + 280 13. 640 + 260 15. 250 + 390 17. 780 + 260 Review. 81 18. 225 + 154 = 225 + 150 + 4 = 19. 315 + 421 21. 540 + 355 23. 172 + 304 20. 437 + 260 22. 248 + 131 24. 517 + 329 148. Give remainders at sight : 1. 134 — 75 = 134-70-5 = 2. 150-83 5. 124-89 8. 100-61 3. 132-94 6. 112-56 9. 124-35 4. 122-56 7. 180-89 10. 132-38 11. 750 — 290 = 750-200-90 = 12. 510-220 14. 820-560 16. 910-550 13. 630-380 15. 730-440 17. 380-290 18. 279 — 154 = 279-150-4 = 19. 386-263 21. 668-325 23. 386-123 20. 457-237 22. 279-125 24. 721-468 149. Give products at sight: 1 . 49 X 4 = 4 forties + 4 nines. 2. 47 x 3 3. 48 x 4 4. 43 x 5 5. 46 x 6 6. 38 X 7 7. 123 X 3 = 3 times one twenty three = three sixty nine. 8. 431 x 2 10. 332 x 3 12. 232 x 3 9. 122 x 4 11. 242 x 2 13. 31 x 24 14. 47 X 25 = k of 47 hundred = llf hundred = 1175. 15. 25 X 38 = 38 X 25 = 1 of 38 hundred = 9f hundred. 16. 32 x 25 18. 44 x 25 20. 49 x 25 17. 25 x 33 19. 25 x 45 21. 63 x 25 150. Give quotients at sight : 1 . 925 -f- 25 = 9J hundred -r- J hundred = 9J -*• 1 = 91 X 4. 2. 875-4-25 4. 725-^-25 6. 575-4-25 3. 625 -s- 25 5. 450-5-25 7. 350-5-25 22 Chapter Two. 151. Oral Problems. 1. Find the cost of a pound of tea at 75 cents, and a piece of ham at 56 cents. 2. A farmer sold 58 sheep from his flock of 121 sheep. How many remained ? 3. What will be paid for 8 pounds of coffee at 35^ per pound ? 4. A laborer received $ 4.88 for four days' work. How much did he earn per day ? 5. At $40 each, how many cows can be purchased for $2000? 6. Bought 20 pounds of sugar at 5^ per pound, and 2\ pounds of butter at 30^. What was the amount of my bill ? 7. A piece of cloth measuring 31^ yards was divided into 2 equal parts. Find the length of each. 8. How many weeks in a year of 366 days ? 9. If I pay 25 cents for 3 pounds of cherries, how many pounds can I buy for $1.25 ? 10. Find the cost of a bushel and a peck of peanuts at the rate of 5 cents per quart. 11. A farmer had 164 acres of land. How much had he left after selling 87 acres ? 12. Find the total number of pounds in 3 tubs of butter weighing respectively 25 pounds, 34 pounds, and 36 pounds. 13. At 60^ per pound, how much tea can be bought for $5.85? 14. A drover paid $ 219 for oxen, at an average price of $ 73. How many did he buy ? 15. What will be the cost of 20 bushels of wheat at $1.04£ per bushel? 16. At 24^ per pound, how many ounces of butter can be bought for 18^? Review. 83 17. A woman pays $ 540 per year for a house. What is the rent per month ? 18. How many weeks in 294 days ? 19. At 72^ per yard, what will be the cost of 2 ft. 11 in. of lace ? 20. How much does a grocer receive for a barrel of flour, 196 pounds, retailed at 3 cents per pound ? 21. If 47 men can do a piece of work in 4 days, how long will it take 1 man to do the same work ? 22. Find the cost of 36 acres of land at $25 per acre. 23. If it takes 3^ yards of cloth to make a coat, how many coats can be made from 24J yards ? 24. How much will be paid for 84 yards of silk at $lf per yard ? 25. If a certain quantity of provisions will last one man 215 days, how long will it last 43 men ? 26. How many square yards are there in a rectangular field 36 yards long and 25 yards wide ? 152. Written Exercises. 1. What is the sum of 94,625; 215; 5172; 819,365; 121? 2. Bought 172 acres of land for $860. What was that an acre ? 3. In a classroom there are 54 pupils ; each pupil spent $ 2.75 for books this year. How much money was spent for books by the whole class ? 4. By the census of 1890, Massachusetts had a popula- tion of 2,238,943 ; in 1900, it had a population of 2,805,346, What was the gain ? 5. How many boxes of strawberries at $.15 a box can I get for $ 1.20 ? 84 Chapter Two. 6. What is a proper fraction? An improper fraction? Define numerator, denominator, a mixed number. 7. Add J, |, |, and ± 8. If 7 pairs of shoes cost $12J, how much will one pair cost ? 10. What is the product of -fa, ^, if, and f$ ? 11. 8ix7| = ? 12. Paid | of a dollar for potatoes, % of a dollar for apples, and ^ of a dollar for sugar. How much did I pay for all ? 13. Divide 2\ by If 14. Find the difference between 4§ and 3f. MULTIPLICATION OF DECIMALS. 153. Oral Problems. 1. When the French franc is worth 19.3 cents, what is the value of the 20-f ranc piece in United States money ? 2. What is the equivalent of 10 German marks, the mark being quoted at 23^- cents ? 3. A man paid 100 pounds sterling for a piano. Find the cost in U. S. money at $ 4.8665 per pound sterling. Note. — $ 4.8665 may be read 4 dollars 86 cents 6 mills and 5 tenths of a mill, a mill being one-tenth of a cent. 4. A meter contains 39.37 inches. How many inches in 100 meters ? 5. One kilogram = 2.2046 pounds. What is the equiva- lent of 1000 kilograms, in pounds ? Note. —.2046 is read 2046 ten-thousandths. 6. How many square yards are there in a piece of ground 40 yards long and 12.5 yards wide ? Decimals. 85 * 7. How many ounces in 2.5 pounds ? 8. Change .75 hour to minutes. 9. Find the perimeter of a square, each side of which measures 10.25 feet. 154. Written Exercises. 1. Multiply 38.4 by 6.37. Place the units' figure (6) of the multiplier under 38.4 the last figure (4) of the multiplicand. 6 times 6.37 4 tenths = 24 tenths = 2.4 ; write .4 under, the multi- 230.4 plier 6, and carry 2 ; etc. Next multiply by .3, 11.52 or fV A x t% = T or - 12 - Write 2 in the hun - 2.688 dredths' place, and carry 1 tenth; etc. Multiply 244 f 08 finally by .07, or T ^. & x T % = T $fo, or .028. Write 8 in the thousandths' place, etc. Ans - * 44 - w °- Note. — By writing the units' figure of the multiplier under the last figure of the multiplicand, and by taking care to place the right-hand figure of each partial product under the corresponding figure of the multiplier, the decimal points in the partial products and the total will naturally fall under the decimal point in the multiplicand. 2. Multiply 12.34 by 56.7. 12.34 While pupils should occasionally begin to ^2 34 gg j multiply by the left-hand figure (5) of the gg j n-ij r\ multiplier, some may prefer to begin with the ft^RQft" 74 04. right-hand figure (7). It will be noted that „. \. 8 £oo the number of decimal places in the product n^r, \ ,,„„'' equals the sum of those in the multiplier and „ *„ r 699.678 2 u . .. . * 699.678 the multiplicand. Multiply as in ivhole numbers, and from the right of the product point off as many decimal places as there are decimal places in both factors. 155. Multiply: 1. 32x2.5 3. 6.4x4.5 2. 3.2x25 4. 7.2x3.75 16. 18.4 x 20.25 17. 11.16 X 42.40 18. 66.6 x 3.3£ 19. 6.24 x 1.75 20. 400.04 x 39.25 86 Chapter Two. 5. 12.8 x 5.7 8. 5.625 x 8.4 6. 9.6 x 1.125 9. 1.875 x 12.8 7. 34.9x2.34 10. 42.36x2.95 Note. — The pupil should correct any error he may make in placing the decimal point by estimating the approximate answer. The answer to example 3, for instance, is more than 2 times 32 and less than 3 times 32. In example 3, it is more than 4 sixes and less than 6 sevens. 11. 1.75 x 64 12. 8.375 x 40 13. 24.5 x 18.2 14. 9.6 x 12£ 15. 7.43 x 3.6 156. Oral Problems. 1. I owned 40 acres of land and sold .25 of it. How many acres did I sell ? 2. A boy bought 15 hens, which was .6 of what he al- ready had. How many had he at first ? 3. A lawyer charged me .11 of the money for collecting $ 100. How many dollars did he charge ? 4. If I earn $ 8 in a week, how much can I earn in 7.5 weeks ? 5. .75 of a class of 44 were promoted. How many were not promoted ? 6. What is the surface of a table 4 feet wide and 6.25 feet long ? 7. .5 of a yard is how many feet ? How many inches ? 8. A man bought 3.5 yards of cloth at $ 5 a yard. What was the price ? 9. 25 miles is .5 of the distance between two cities. What is the distance? 10. In a box were 100 oranges; .08 of them became spoiled. How many sound ones were left ? Decimals. 87 157. Written Problems. 1. How many yards are there in 25 pieces of carpeting if each piece contains 32.75 yards ? 2. A mill uses 95.6 tons of coal per day. How many tons will it use in 42.25 days ? 3. A cubic foot of water weighs 62.5 pounds ; ice is .92 as heavy as water. What is the weight of a cubic foot of ice ? 4. I bought 3 loads of wood, the first containing 1.04 cords, the second 1.05 cords, and the third .946 cord. What did it cost me at $ 4.50 a cord ? 5. A gallon of water weighs 8.33 pounds. What is the weight of a gallon of milk which is 1.03 times as heavy as water ? 6. A wheel in making one revolution travels 15.03 feet. How far will it travel in 25 revolutions ? 7. A ship sails 18.54 miles in an hour. How far will she sail in 15.5 hours ? ^. Find the cost of concreting a cellar 24.5 feet long by 14.25 feet wide, at 30 cents per square foot. 9. A quantity of provisions will last 25 men 12.75 days. How long will it last one man ? 10. Two men start from the same place and travel in op- posite directions, one at the rate of 3.85 miles per hour, and the other at the rate of 4.12 miles per hour. How far apart will they be at the end of 13 hours ? Make a diagram. DIVISION OF DECIMALS. 158. Divide 42 by 2.1. Changing the decimal fraction in the divisor to a common fraction, we have 42 -2^ = ^-H= ^ x tf = *&> 42-2.1 = 420-7-21. Note. — When we change the divisor 2.1 to 21, we have multiplied it by 10, and the same change must be made in the dividend. 88 Chapter Two. Make the divisor a wJiole number, and make a correspond- ing change in the number of decimal places in the dividend. This reduces the numbers to the same denomination. If neces- sary to complete the operation, ciphers may be annexed to the dividend. The number of decimal places in the quotient is equal to the number in the dividend as changed. 9. 50 -r- .25 10. 72 - .5 11. 960 - .03 12. '.847 -.007 13. 27 -=- .002 14. 10 -r- .8 15. 1.263 -f- .03 16. 19.63 -5- .013 17. Diyide 196.3 by .013. Remove the decimal point in the divisor three places to the right, and make a corresponding change in the dividend, adding two ciphers. To show where the decimal point originally be- longed, draw a cancellation mark through it, instead of erasing it. When the divisor is thus made a whole number, the decimal point In the quotient will be placed under (or over) the new decimal point In the dividend. 1.736 - 16 17.36 -j- .16 .01736 -i- 1.6 .1085 Ans. 108.5 Ans. .01085 Ans. 159. Written Exercises. Divide : 1. 80-2.5 2. 8+2.5 3. 840 -f- 1.2 4. se^A 5. 36 -.9 6. 12.6 -f- 6.3 7. 48 + 15 8. 18.36 + .6 L6)1.7360 /16.)17/36.0 l/6.)/0.17360 Decimals. 18. .504 --.024 26. 392 -- 3.2 19. 5.04 -- .24 27. 48 -5- 3000 20. 50.4 -- 2.4 28. 92 -*- .23 21. 504 -5- 24 29. .875 - 125 22. 168 -s-,7 30. 381.17 -f- 8.11 23. 36 -5- .12 31. .624 -r- 9.75 24. .875 -5- .25 32. 48.195 -5- 3.57 25. 123.6 -v- .01 33. 829.31 -5- .019 89 160. Divide 381.6 by 95.032. Note. — The sign (+) after the last figure of the quotient indicates that there is a remainder. 4.015 + 95/032.)381/ 600.000 380128 147200 95032 521680 161. Divide, carrying out the quotient to 3 places of decimals 34. 31 -5- 13 35. 4.5 -5- 17 36. 920.07-5-46 162. Write answers at sight : 37. 7.049-5-1.6 38. 81.22-5-3.275 39. 246.3 -5- 93.473 Note. — To multiply .042 by 100, the decimal point is moved two places to the right ; i.e. .042 x 100 = 4.2 ; .042 x 200 = 4.2x2 = 8.4. 1. .042 x 200 2. .13 x 300 3. .014x50 4. 8.1 x 60 5. 40 x .7 6. 25 x .8 7. 234 x. 2 8. .73 x 30 9. .121x4000 10. .061x500 11. .03x1000 12. .012 x 700 Note. — Remember that 369 -=- 1000 = T 8 ^ = 369 thousandths =.369, To divide 369 by 3000, therefore, divide .369 by 3. 90 Chapter Two. 13. 369-^-3000 17. 2460 + 3000- 21. 4.68 + 20 14. 219 + 300 18. 196 + 4000 22. 30.5 + 500 15. 48.6 + 60 19. 6 + 500 23. 18.8 + 200 16. 1.89 + 90 20. 27.9 + 300 24. 248 + 4000 163. Written Exercises. 1. 1728 + 1200 2. 172.8 + 1200 3. 1.728 + 1200 1200 )17.28/ 1200 )1.72/8 1200 ).Ol/728 1.44 Ans. .144 Ans. .00144 Ans. Cancel the ciphers in the divisor, and remove the decimal point in the dividend a corresponding number of places to the left, prefixing ciphers if necessary. 164. Divide: 1. 2436 + 3000 7. 45 + 800 2. 136.5 + 1300 . 8. 25.2 + 240 3. 84.8 + 80 9. 345.6 + 1200 4. 100.1 + 700 10. 4004 + 110 5. 1 + 40 11. 5.28 + 60 6. 2.2 + 50 12. 907.5 + 1500 165. Oral Problems. 1. I cut 8.72 yards of cloth into 8 equal pieces. How long was each piece ? 2. I divided .75 of a pound of candy equally among 3 girls. What part of a pound did each receive ? 3. I divided .5 of a pound of cherries among 4 children. What part of a pound did each receive ? 4. 49 rods is .7 of the distance round a field. How many rods of fence will enclose the field? 5. 24 yards of matting cover .8 of my floor. How many yards more must I buy? Decimals. 91 6. 40 pounds are .4 of my weight. What do I weigh ? 7. I spent 2.5 dollars, which was .5 of what I had. How much had I ? 8. 36 square inches are .25 of a square foot. How many- square inches in a square foot ? 9. A collector receives .05 of all the money he collects. How much did he collect to earn 9 15 ? 10. At 75 cents each, how many chairs can be bought for $12? 166. Written Problems. 1. If 35.84 cubic feet of water weigh a ton, what will be the weight of 2458.6 cubic feet ? * 2. How many francs are there in $150? (A franc equals 19.3^.) 3. If a barrel of flour costs $5.75, how many barrels can be bought for $ 258.75 ? 4. If $ 640.05 are paid for 75.3 tons of coal, what is the price per ton ? 5. There are 31.5 gallons in a barrel. How many bar- rels are there in 2787.75 gallons ? 6. I have 96 cubic feet of wood ; this is .75 of a cord. How many cubic feet in 1 cord ? 7. A man earns $162 in 13.5 weeks. What are his wages per week? 8. I bought a farm of 71.5 acres for $6220.50. What did it cost me per acre ? 9. There are 2150.4 cubic inches in a bushel. How many bushels are there in 9676.8 cubic inches ? 10. The wheel of a bicycle is 7.25 feet around. How many times will it turn in going a mile, or 5280 feet ? gi Chapter Two. UNITED STATES MONEY. FRACTIONAL PARTS OF A DOLLAR. 167. Oral Problems. 1. How many 50-cent base-balls can be bought for f 15 ? (15 -r- 1, i.e. 15 x 2) 2. How many 75-cent base-balls can be bought for $ 15 ? (15 h- f, i.e. 15 x |) 3. At 75^ per pound, how much tea can be bought for $ 1 ? 4. How many hats, at $1.25 each, can be bought for $15? (15 ^-1|) 5. Paid $16 for coffee at 25^ per pound. How many pounds were purchased ? 6. At 33^ per pound, how many pounds of butter can be bought for $ 32 ? 7. Find the number of yards of ribbon, at 12-J-^ per yard, that will cost $45. 8. At 6J£ per bar, how many bars of soap will cost $ 11 ? 9. If 4 pieces of violet soap are sold for 25^, how many can be bought for $ 9 ? 10. $ 24 is paid for corn at 75^ per bushel. How many bushels are bought ? 11. I spent $30 for lace at 66^ per yard. How many yards did I buy ? 12. For $ 36 how many pairs of rubber shoes can be bought at 37^ per pair? 13. Oats are 62^ per bushel. How many bushels will $40 buy? 14. A farmer pays 87^ per bushel for seed rye. If his bill amounted to $ 21, how many bushels did he purchase ? United States Money. 93 15. A storekeeper sold $ 33 worth of collars, at 16f ^ each. How many did he sell ? 16. At the rate of 3 for 50^, how many collars can be bought for $25? 17. Corn is worth 20^ per can. How many cans will cost $ 32 ? 18. Find the cost of 35 yards of cloth, at $ 1.25 per yard. 19. At $ 1.25 per yard, how many yards of cloth can be bought for $ 35 ? 20. How many pairs of gloves, at $ 1.75 per pair, will cost $ 28 ? 21. When coal is $ 5.25 per ton, how many tons can be bought for $ 42 ? 22. Cost of 16 pairs of shoes at $ 2.75 ? 23. 33 jackets at $ 3.33J ? 24. 18 yards cloth at $ 2.16| ? 25. Paid $ 26 for cloth at $ 2.16| per yard. How many yards did I buy ? 26. Find the cost of 16 pairs of skates at $ 1.87^- per pair. 27. If sheep cost $3. 12^ each, how many can I get for $ 75 ? 28. How many 25-cent balls can be bought for $ 8.75 ? 29. Divide 775 by 25. 30. Divide $8.25 by 75^. 31. How many square feet are there in a lot 96 feet long, 100 feet wide ? In a lot 96 feet long, 25 feet wide ? 32. Find the total cost of 32 head of cattle at $ 75 per head. 33. How much must be paid for 32 cows at $37.50 each ? 34. If sheep are worth $3.75 each, how much will a farmer receive for 32 sheep ? 35. If a train goes at the rate of 25 miles per hour, how many hours will it take to go 675 miles ? 16 oz. Xl7 112 16 272 oz. Add 4 oz. 276 oz. 4qt. 37 gal. 3 qt. 151 qt. 94 , Chapter Two. DENOMINATE NUMBERS. Note. — For the tables of Denominate numbers used in these les- sons, see section 93, pages 43-44. 168. Written Exercises. 1. Change 17 lb. 4 oz. to ounces. Since there are 16 ounces in 1 pound, in 17 pounds there are 272 ounces, etc. Add 4 oz. Arts. 2. Change 37 gal. 3 qt. to quarts. In this example, we are to multiply 4 quarts (the number in a gallon), by 37, and to add 3 quarts to the product. In practice, \§± q^ Ans. however, 4 is taken as the multiplier, and the three quarts are added in. We say 4 sevens are 28, and 3 are 31, writing the 1 ; 4 threes are 12, and 3 are 15. 3. Change 45 bushels to quarts. Write as here shown, placing 4 pk. 8 qt. above pecks the number of pecks 45 k u . Opk. qt. in a bushel, and above quarts the jca pk # 1440 qt. number of quarts in a peck. Multi- . .. 1At i , ply 4 pecks by 45, and write the product, 180 pecks, in the proper column ; multiply 8 quarts by 180, etc. Change : 4. 63 qt. 1 pt. to pints. 5. 27 bu. 3 pk. to pecks. 6. 48 pk. 7 qt. to quarts. 7. 84 pk. to pints. 8. 7 mi. 60 rd. to rods. 9. 13 hr. 20 rnin. to minutes &0. 18 wk. 3 da. to days,, Denominate Numbers. 95 11. Change 151 quarts to gallons and quarts. Write above 151 quarts the number of quarts 4 Q ^ in a gallon. Divide 151 by 4 to obtain the num.- 15T~ot~ ber of gallons, 37. Write the remainder, 3, in ^Z ;~ 7; — 7~ A f . . 6 .' ' ' 37 gal. 3 qt. An& the column of quarts. 12. Change 228 inches to yards and feet. Divide the number of inches, 228, by 12, to 3 f^ ^2 in obtain the number of feet, 19. Write this to -in ft 228 in the left of 228 inches. Reduce to yards by divid- a v a 1 f 4- An* ingby3. 13. 87 pints to quarts and pints. 14. 250 feet to yards and feet. 15. 1650 rods to miles and rods. 16. 864 hours to weeks. 17. 296 quarts to bushels and pecks. 18. 315 ounces to pounds and ounces. 19. 743 months to years and months. 20. 15,000 minutes to days and hours. 21. Add 3 ft. 6 in., 9 ft. 5 in., 12 ft. 3 in. Write the feet in one column and the inches 3 ft. 6 in. in another. The sum of the column of inches is 9 ft. 5 in. 14 inches, or 1 foot 2 inches. Write 2 inches, 12 ft. 3 in. and carry 1 foot to the next column. 25 ft. 2 in. Ans. 22. 30 min. 15 sec. + 30 min. 18 sec. + 45 min. 24 sec. 23. 9 yr. 3 mo. -f 18 yr. 7 mo. + 22 yr. 2 mo. 24. 19 wk. 4 da. + 7 wk. 5 da. + 8 wk. 25. 9 mi. 169 rd. + 84 rd. -f- 3 mi. 67 rd. 26. 7 yd. 1 ft. + 33 yd. -f- 19 yd. 2 ft 27. 18 gal. 1 qt. + 16 gal. 2 qt. + 15 gal. 3 qt 28. 5 pk. 3 qt. + 6 qt. + 7 pk. 1 qt. $6 Chapter Two. 29. 24 bu. 3 pk. + 24 bu. 3 pk. + 24 bu. 3 pk. 30. 12 qt. 1 pt. + 12 qt. 1 pt. + 12 qt. 1 pt. + 12 qt. 1 pt 31. Multiply 12 qt. 1 pt. by 7. 7 times 1 pint = 7 pints =3 quarts 1 pint. Write 12 at 1 pt 1 pint in the proper column, and carry 3 quarts. „ n 7 times 12 quarts = 84 quarts. Carrying 3, we <*» 7 -j , a get 87 quarts. 32. 12 qt. 1 pt. x 4. 37. 15 wk. 3 da. x 5. 33. 24 bu. 3 pk. x 3. 38. 7 yr. 3 ino. x 10, 34. 5 pk. 3 qt. x 9. 39. 40 min. 35 sec. x 2. 35. 18 gal. 1 qt. x 8. 40. 9 ft. 5 in. x 12. 36. 33 yd. 1 ft. x 6. 41. From 25 ft. 3 in. take 18 ft. 7 in. Take 7 inches from 1 foot 3 inches, or 25 ft. 3 in. 15 inches. Carry 1 foot to 18 feet, making — 18 ft. 7 in. 19 feet, etc. 6 ft. 8 in. Ans. 42. 50 min. 13 sec. — 27 min. 30 sec. 43. 12 yr. 1 mo. — 5 yr. 11 mo. 44. 50 wk. 4 da. - 18 wk. 6 da. 45. 25 ft. -18 ft. 7 in. 46. 33 yd. 1 ft. - 18 yd. 2 ft. 47. 240 gal. 1 qt. - 94 gal. 2 qt. 48. 83 pk. 3 qt. - 59 pk. 1 qt. 49. 170 bu. 1 pk. - 85 bu. 2 pk. 50. 135 qt. 1 pt. - 67 qt. 1 pt. 51. Divide 87 gal. 2 qt. by 5. Dividing 87 gallons by 5, we get 17 gallons, and 2 gallons remainder. Change 2 gallons 5 )87 gal. 2 qt. to 8 quarts, add in 2 quarts, making 10 quarts. 17 gal. 2 qt. Ans. Dividing 10 quarts by 5, we get 2 quarts. Denominate Numbers. 97 52. 50 min. 35 sec. -7- 5 57. 387 gal. -*- 6 53. 156 yr. 9 mo. ^ 9 58. 222 bu. 3 pk. -*- 9 54. 73 wk. 2 da. ^ 3 59. 150 qt. -*- 4 55. 50 mi. 135 rd. -f- 7 60. 75 bu. -f-8 56. 253 yd. 1 ft. -- 10 61. Divide 87 qt. by 43 qt. 1 pt. Change the divisor to 87 pints. 43 ^ ^ p^ \ gj ^ Change the dividend to the same de- g feet- high. How many square feet in the floor ? *.'.•?•>•? »* , ,• Draw a rectangle to represent the ceiling. Write the dimensions in their proper places, and write in the centre the number of square feet in its surface. Draw diagrams of the four walls ; give dimensions and surface of each. 19. How many faces has a cube ? If one edge of a cube measures 4 inches, how many square inches are there in the entire surface ? Suppose you wish to make a cube out of a single piece of paste- board. Make a drawing to show the shape of the piece needed, without allowing anything for overlapping parts. 20. The United States government charges a duty of 4^ per square yard on imported cotton cloth. What duty must the importer pay on a piece containing 24 yards, f yard wide? 21. What will be the cost at $ 1 per square yard for making a sidewalk 12 feet wide and 30 feet long? BILLS. 173. New York, Oct. I, 1904. Mrs. William Johnson, Bought of Furey & Company. 1904 Aug. 18 15 19 1,4 yd. Carpet 8 Oak Chairs 1 Rocker 18 yd. Oil-cloth f .90 1.75 .50 12 — 27 1 Parlor Suit 75 — Sept. 19 6 Kitchen Chairs .75 1 Table 4 50 26 86 yd. Matting M 9 io2 Chapter Two. ,1.- Copy 'jthe . bill on the preceding page. Supply the missing amounts. 2. Charles W. Wise has bought the following goods of Thos. F. Farley & Co. : Jan. 3, 1904, 50 pounds of sugar, at h\$ ; 4 pouDds of tea, at 62-£/. Jan. 4, 10 pounds of coffee, at 32|^ ; 2 barrels of flour, at % 5.75. Jan. 9, 24 bars of soap, at 16|^ ; 42 pounds of starch, at 8^. Make out a bill dated Feb. 1, 1904. 3. Make out a bill for the following articles bought dur- ing March and April. Supply the names of buyer and seller, also the dates : 23£ yards of silk, at 80^; If yards of lace, at $2.40; 64 yards of muslin, at 6 J^ ; 8 spools of sewing silk, at 7^ ; 4 pairs of stockings, at 65$; 6 yards of linen, at 87|^; -J- dozen collars, at $ 2.10. 4. Make out a bill for the following goods, bought June 15: 3 cases of torpedoes, at $ 2.20 ; 12 boxes of firecrackers, at $1.62-J-; 3 gross pinwheels, at $1.35; 5 gross sky- rockets, at $ 3.25 ; 2 dozen balloons, at $ 2.25 ; 45 lanterns, at 9£ Note. — The date is written only at the top of the bill when all the articles are bought at one time. SHORT METHODS — REVIEW. If the school is to train for life, it must accustom pupils to use modes of calculation followed in the business world. In their previous work, pupils have employed $^ instead of 25?, -$£ instead of 12^?, etc. They have, for instance, found the cost of 32 pounds at 25? per pound, by multiplying $£ by 32. While the result in example 4 is the same, 25 pounds at 32?, the analysis is dif- ferent. The following is suggested : 100 pounds at 32? would cost $ 32, \ of 100 pounds would cost \ of 432, or #8. The rule generally given for the multiplication by 26 is to annex Review. 103 two ciphers to the multiplicand and to divide by 4. In practice, the ciphers need not be annexed actually or mentally. To multiply 19 by 25, the pupil divides 19 by 4, getting 4 for quotient ; to this he adds 75 for the 3 remainder, getting 475 for the result. 174. Oral Exercises. 1. Multiply by 25 : 16, 19, 21, 23, 25, 29, 33, 36, 42, 48. 2. How many square feet in a lot 84 feet long, 25 feet wide? 3. What is the weight of 25 barrels of flour, each weighing 196 pounds? 4. Find the cost of 25 pounds of coffee at 32^ per pound. 5. What will a woman have to pay for 25 yards of silk at $1.60 per yard? 6. A man sold 25 cows at $44 each. How much did he receive for them? 7. Multiply 64 by 12i 8. Find the cost of 12^- bushels of wheat at 96^ per bushel. 9. At $12.50 per barrel, how much should I pay for 56 barrels of pork? 10. How many pens in 12^- gross? (144 to gross.) 11. Find the cost of 121 pounds of tea at 56 jt per pound. 12. How many square yards in a field 96 yards long, 75 yards wide? 175. Sight Exercises, To multiply 427 by 25 the pupil considers 4 as the divisor. He writes on his paper 1, then 0, then 6, annexing 75 for the 3 remaining. Ans. 10,675. Example 5 : 25 x 686 is the same as 686 x 25. Example 9 : To multiply by 250, consider three ciphers annexed to the multiplicand. 104 Chapter Two. Example 11 : Divide by 8, annexing two ciphers to the quotient when there is no remainder. Annex 12£ when the remainder is 1 ; 25, when the remainder is 2 ; etc. Example 19: Consider three ciphers annexed and divide by 8. Write only the answers : 1. 837 x 25 8. 25 x 2174 15. 12 J x 1084 2. 763 x 25 9. 837 x 250 16. 12£ x 2196 3. 934 x 25 10. 763 x 250 17. 12£ x 3670 4. 508 x 25 11. 864 x 12£ 18. \2\ x 6281 5. 25 x 686 12. 776 x 121- 19. 864 x 125 6. 25 x 301 13. 236 x 12£ 20. 776 x 125 7. 25 x 1039 14. 404 x 12\ 21. 125 X1020 176. Sight Exercises. Pupils do much unnecessary work in rearranging numbers and in writing fractions over again with a common denominator. A few of these examples should be written on the blackboard from time to time, and the teacher should require the pupil to write nothing but the answers. Add: 1. 3£ + 5£ 4. 11J + 4J. 7. 8i + 6J 2. 4£ + 8f 5. 7f + 9^ 8. 15| + 8J 3. 9| + 7f 6. 5f + 2| 9. 9f + 5£ 177. Subtract at sight : 10. 23^~19| 14. 9£-2* 18. 35J -Si 11. 16f - 9f 15. lOJ-5^ 19. 11* -6* 12. 18f - S\ 16. 14J-8A 20. 43A-8J 13. 15f - Si 17. 27£-7| 21. 50J- - 4f Review. 105 178. Multiply at sight, 18| x 4. f x 4 = 3. 4 eights are 32, and 3 are 35 (put down 5). 4 ones are 4 and 3 are 7 (put down 7). Ans. 75. The pupil should write only the answers. 22. 27} x 10 27. 15} x 3 32. 37} x 3 23. 33} x 12 28. 13} x 4 33. 45|x5 24. 16f x8 29. 20} x 11 34. 23} x 4 25. 17|x8 30. 40f x5 35. 17} x 6 26. 19|x6 31. 16|x7 179. Divide at sight. "When the divisor is an integer less than 12, the pupil should not reduce the mixed number in the dividend to an improper fraction, by 3, the pupil first gets the whole number of the Ans. 89}. In dividing 248£ by 4, the pupil obtains 62 as the quotient of 248 by 4 ; he then finds \ of \, which is \. Ans. 62} In dividing 202£ by 5, the quotient is 40, and the remainder is 2} which is reduced to f . One-fifth of this is } Ans. 40} In dividing 183| by 6, the quotient is 30 with a remainder of 3£, Ans. 30 J|. 46. 7 )97^ 47. 10 )87} 48. 4 )66} 49. 3 )94} 50. 5 )83} SIGHT APPROXIMATIONS. 180. Give approximate answers in whole numbers. Solve for the exact answers. 1. 17 & X 3fJ; or, about 17 x about 4. 2. 25^ -7- 1|; or, about 25 -r- J nearly. or^. *of¥ = lf 36. 3)45f 41. 8)37} 37. 4)56} 42. 9)48} 38. 12)36} 43. 6)25} 39. 5)72} 44. 7)10} 40. 11)834- 45. 6)751 io6 Chapter Two. 3. 61 x H 7. 799f|-=-99H 4. 300^ + llff 8. 7t%x7A 5. 86|xH *• TixllA 6. 35J + 3H 10. M* x f 181. Give answers in whole numbers : 1. 5.75 x 9.999; or, 5.75 x 10 nearly. 2. 24.002 + .4999 ; or, 24 -?- nearly f 3. 25.125x11.834 7. 799.9 x .103 4. 36.843 -j- 6.105 8. 7.999x7.999 5. 86.4 -.983 9. 7.001x12.003 6. 32.04x5.001 10. 64.001 -f- .249 182. Give the cost, approximately, of : 1. 49 horses at $ 199 each. ($200 x 49.) 2. 199 yd. 2 ft. 11 in. of cloth at $2.50 per yard. 3. 3 lb. 15 oz. of butter at 25? per lb. 4. 398 coats at $ 12 each. 5. 7 bu. 3 pk. 7 qt. potatoes at $2 per bushel. 6. 798 base-balls at 25 cents each. 7. 19 gal. 3 qt. 1 pt. alcohol at $2.49 per gallon. 8. 995 lb. tea at 59f cents per pound. 9. 7 houses at $4995 each. 10. 507 pounds of hay at 99 cents per 100 pounds. 183. Oral Eeview Exercises. 1. What is | of 60 ? fof35? 2. A man sold a boat for $ 8, which was \ of what it cost him. What did it cost him ? 3. A man having $35, gave away -J- of it. How much had he left ? Review. 107 4. How many inches are there in f of a yard ? f of a yard ? -J of a yard ? 5. If 6 eggs cost 12 cents, what will 5 dozen cost ? 6. How much is f less \ ? £ less i ? 7. Change to improper fractions : 7$, 9J, 6f, 2^, 6£. 8. How many apples at 2^ apiece are worth as much as 4 peaches at 5fi apiece ? 9. Which is the greater and how much : f of $ 24, or | of I 25 ? 10. Change to mixed numbers : &£-, A^, -fj, - 4 /, -^. 11. There are 45 pupils in school and -J of them are girls. How many are boys ? 12. Add 8J and 7$. 5f and 1\. 13. If it takes 5 men 15 days to do a piece of work, how long will it take 10 men to do it ? 14. What will 2 bushels of corn cost, if £ peck costs 15 cents ? 15. If it costs 25 cents to set one shoe, what will it cost to shoe a span of horses all around ? 16. Bought 5 yards of ribbon at 16^, and 3 yards of linen at 75^, and gave a two-dollar bill. What was my change ? 17. If 7 yards cost 84^, how many yards can be pur- chased for $1? 18. If 6 oranges cost 15^, how much will 8 cost ? 19. 1-J- pecks of peanuts cost $ 0.48 ; what will one quart cost? 20. Two boys walked in opposite directions ; one walked 5 miles an hour, the other 4 miles an hour. How far apart were they in six hours ? 21. If I of a yard of cloth cost 6^, how much cloth can be bought for 40? ? 108 Chapter Two. 22. At £ a dollar per day for board, how many days' board can you get for $ 7.50 ? 23. Charles picked £ peck of berries, William £ peck, and Alfred £ peck. How much did they all pick ? 24. How much more is } of 80^ than f of 75^ ? 25. A boy bought 3^ pounds of butter for his mother. How many ounces did he buy ? 26. If a man is 50 years old now, how old was he 22 years ago ? 27. Mary works 4 hours and 40 minutes, and Nellie works 2 hours and 20 minutes. How many hours do they both work ? 28. If you should receive 15 cents at one time, 26 cents at another time, and 14 cents at another time, how much would you receive in all ? 29. If you had f of a dollar, and should buy a pound of soda for 8^ and a pound of tea for 45^, how much would you have left ? 30. If you give a boy $ 10, how many mills do you give him? 31. 50-12-9-19 = 32. 72—7 times 9 = what number? 33. 45 is how much less than 5 times 12? 34. (f of 80) + 25 = 35. (35 + 15) -(14 -9) = 36. $ = how many sixths ? 37. 2\ — how many fourths? 38. Give the exact divisors of 20. 40. From \ take J. 39. Give the three factors of 30. 41. 2\ + \ — \ = 42. At 12 cents a dozen, what will a gross of buttons cost? Review. 109 43. How many inch cubes will exactly cover a square foot of surface? 44. What does f of anything mean ? 45. 1 gallon 2 quarts and 1 gallon 1 quart are how many quarts ? 46. If 4 yards of muslin cost 48 cents, how much will one-third of a yard cost ? 47. Paid $4.86 for 6 bushels of rye. What was the price per bushel ? 48. Bought 3 dolls at 49 cents each. Total cost ? 49. If 12 hats cost $ 7, what will be paid for 36 hats ? 50. If 2 pounds and 5 ounces butter cost 74 cents, what will be the cost of 3 pounds and 2 ounces ? 51. How many bottles holding 1\ pints will be needed to contain 2\ gallons ? 52. A bag of flour contains \ of a barrel of 196 pounds. How many pounds does the bag contain ? 53. What will be the cost of a dozen heads of cauliflower at the rate of 2 for 25 cents ? 54. Twenty examples are given out. A pupil that cor- rectly answers all receives 100 per cent. What per cent will a pupil receive that solves 16 examples ? 55. A woman receives $40 interest a year. How much does she receive in 3 years and 6 months ? 56. A man bought some cows at $ 35 each, and the same number at $ 45 each. What was the average price ? 57. A girl received 100 credits in each of three studies, and 80 credits in the fourth. What was the total number of credits in the four studies ? What was her average ? 58. A square floor contains 144 square feet. How many feet long and wide is it ? no Chapter Two. 59. -J yard cloth costs $ f . What is the price per yard ? Note. — In dividing one fraction by another mentally, reduce both to their common denominator. | price of a yard = $ £. ■& price of a yard = $ fo Multiplying by 12, 8 times price of a yard = $ 9. 60. A man owning f of a vessel sells f of his share. What part of the vessel does he then own ? 61. A barrel contains 196 pounds of flour; the barrel weighs 24 pounds. What is the weight of both? 62. A family uses 3J pounds of sugar per day. How long will 24^- pounds last ? 63. How much will be the cost of 3 pounds of 25-cent coffee and 1 pound butter at 36^ ? 64. If | of a pound of candy costs 30^, what will be the cost of J of a pound ? Note. — 6 eighths cost 30^, what will 7 eighths cost ? 65. A tailor has a piece of cloth containing 2\ yards; he sells If yards. What part of the piece does he sell ? 66. How many quarts in 1 bushel 1 peck and 1 quart? 67. Keduce ff to lowest terms. 68. 24 J- yards of cloth are used for 7 coats. How many yards in each coat ? 69. If cloves are worth 20^ per \ pound, how much will be paid for 7 ounces? 70. At 3 oranges for 5^, what will be the cost of 1^ dozen oranges? 71. My purchase amounts to $1.29. I give the store- keeper a $2 bill. How much change do I receive? 72. A bushel of nuts was sold for 5^ per quart. How much money did it bring ? Review. ill 73. How many days in the summer months, June, July^, and August ? 74. John had 40 cents. After earning 24 more, he spent his money for marbles at 4 cents each. How many did he buy? 75. George was sent to the store with 50^. He bought 6 pounds of rhubarb at 2^ a pound, and two bunches of radishes at 5^ a bunch. How much money had he left ? 76. At $ 10 a ton what will be the cost of 1000 pounds ? 77. There are 16 rooms in a building with 50 desks in a room. How many desks in all ? 78. Edgar earned $2.75 one week, and $2.50 the next week. How much did he earn in both weeks ? 79. $ 6 is f of how many dollars ? 80. Charles began work at 2.45 p.m. and stopped at 5.15 p.m. How long did he work ? 81. 29 + 18 + 30 + 9 + 8 + 7=? 82. ^ of 22 is how many times 4 ? 83. Bought a horse for $45 and a saddle for $35, and then sold them, gaining $20. For how much were they sold? 84. Add these numbers : 12, 15, 9, 13, 11, 7, and 24. 85. If you buy 6 yards of tape at 7 cents a yard, and 4 yards of silk at 7 dollars a yard, what will you give for both tape and silk ? 86. Bought 8 firkins of butter for $72, and gave 2 of them for 9 yards of cloth. What was a yard of the cloth worth ? 87. Mr. Brown mixed 3 pounds of black tea worth 40 cents a pound with 1 pound of 60-cent green tea. What is the mixed tea worth a pound ? 112 Chapter Two. 184. Written Eeview Exercises. 1. In 6987 days how many minutes? 2. Find the cost of 1,588,000 pounds of coal at $5.98 a ton. 3. How many cords of wood, at $ 7.85 a cord, can be purchased for $ 59,730.65 ? 4. Divide $ 3,245,530 by 468. 5. Bought 8 bushels 3 quarts valuable seed at seven dollars and eight cents a quart. How much did the seed cost? 6. What is the cost of 19 gallons 2 quarts of cologne at 90^ a quart? 7. Divide f of $ 60,800 equally among 75 persons. 8. Bought a house for $23,650, and land for $73,640. For how much must I sell them to gain $ 4500 ? 9. Find the greatest common divisor of 45 and 135. 10. A grocer bought 7200 gallons of oil, one-third of it leaked out, and he sold the remainder at 25 cents a gallon. How much did he receive for it ? 11. From two and four-tenths yards take .445 of a yard. 12. Add the numbers from 490 to 505 (inclusive). 13. If 56 pounds of sugar cost $ 3.08, what will 24 pounds cost? 14. If 42 gallons 3 quarts 1 pint of cream cost $ 27.44, what will 32 pints cost ? 15. A man's bill at a provision store was $ 6.66. He had bought two pecks of peas for $0.54 and some beans for $ 0.36. The rest of the bill was for sirloin steak at $ 0.32 per pound. How many pounds of meat had he bought? 16. From 1,890,070 take 990,979. 17. If a train travels 45 miles per hour, how far will it go from half-past 9 in the morning to a quarter of 7 in the evening ? Review. 113 18. A mechanic saved $ 35 per month for 11 months, and $ 20 the twelfth month. His expenses averaged $ 3 each day of the year. What were his daily wages for the 300 days he worked ? 19. A 160-acre farm consists of 5 fields. The first con- tains 17.38 acres, the second 29.4 acres, the third 35.073 acres, the fourth 25.875 acres. How many acres are there in the fifth field ? 20. How many seconds in 7 hours 15 minutes ? 21. Find the total cost of 2 dozen rockets at $7.50 per gross, 3 dozen Roman candles at $9.60 per gross, and 24 dozen pin wheels at $ 1.35 per gross. (1 gross = 12 dozen.) 22. Three lots of tea were sold for $330. The second contained twice as much as the first, and the third three times as much as the first. The third lot contained 330 pounds. Find the selling price of the tea per pound. 23. A barrel of molasses contained 40 gallons. One- fourth of it leaked out. If the molasses cost 45 cents per gallon, what price must be charged for the remainder so that there will be no loss? 24. If 12£ dozen rockets cost $5.75, what will 15 dozen cost? 25. Show by drawings that -J = -j^, and that f = |. 26. Write the first five prime numbers that are greater than 7. 27. Find the greatest common divisor of 1220 and 2013. 28. Find the least common multiple of 12, 15, 14, 6, 21, 21, and 24. 29. Find the prime factors of 1140. 30. Add 8fc -£, f and } of 7*. 31. From 14^ pounds of butter, 5f pounds were sold to one person and 3£ to another. How much remained ? H4 Chapter Two. 32. A man bought 4 bushels of wheat for 3f dollars. What fraction of a dollar did one bushel cost? 33. If f of a bushel of oats will last a horse one day, how long will 4J- bushels last? 34. In two months Ann will be 15 years old. How old was she nine months ago ? 35. A boy has to walk from his home to a house If miles east of his home, from there to a place 2\ miles west of his home, and then home. How far has he to walk ? 36. I lost f of my money, then found f of what I had lost, and then had 64 cents. How much had I at first ? 37. Quotient 24J, divisor 3^. What is the dividend? The product is 2|, and one factor is -§. What is the other factor ? 38. Bought Z\ yards of muslin at 7 cents a yard, 5^- yards of ribbon at 3J cents a yard, and 2\ yards of cloth at $ 1.75 per yard, and gave a ten-dollar note in payment. How much change did I receive? 39. Write seven million nine thousand nineteen. 40. A milliner sells 3 pieces of ribbon at 18 cents per yard. They measure 4| yards, 3f yards, and 5^- yards respectively. What does she receive for the ribbon ? 41. How many feet and inches in T 5 ^- of a yard ? 42. To make powder, a man mixes 1\ pounds of saltpetre, IfV pounds of sulphur, and as much charcoal as sulphur. How many pounds of powder will there be ? 43. Four men form a partnership ; the first furnishes -£■ of the capital, the second -f, and the third -j^-. What frac- tion of the capital is furnished by the fourth ? 44. I pay 15 cents more for a half-pound of tea than I pay for a quarter-pound of the same tea. What is its price per pound ? Review. 115 45. After doing £ of a piece of work, a man requires 3 days more to finish it. How many hours does he take to do the whole work if he works 8 hours per day ? 46. If 1 pound 7 ounces of coffee cost 46 cents, what will 3 pounds 9 ounces cost ? 47. Add 6 hours 50 minutes and 17 hours 10 minutes. 48. 15 men do a piece of work in lOf days. How long would it take 5 men to do the same work? 49. To make a cloak, 3 yards of cloth 1^ yards wide are required. How much cloth £ yard wide would be required? 50. In 3 years 4 months a gas company manufactures 4,200,000 cubic feet of gas. How many cubic feet are manufactured per year ? 51. If 2| dozen hats cost $80, what will be the cost of 3 hats? 52. A boy hires a boat at 20 cents per hour. How much should he pay if he uses it from 20 minutes before 9 a.m. until 10 minutes past 1 p.m. ? 53. A and B kill an ox. A takes f and B the remainder. If B's share weighs 361^ pounds, what is the weight of the ox? 54. A grocer buys 30 dozen eggs at 18 cents per dozen. He sells them at the rate of 15 eggs for 25 cents. What is his profit ? 55. How many cents in T 5 g- of a dollar ? 56. What fraction of 18f is 6f ? ' Suggestion. — What fraction of 18 is 6 ? Which is the divisor ? 57. A farmer buys a horse for $140, and sells it at an advance of -fa of the cost. What is the selling price ? 58. In 1903, A was 36 years old and B was If times as old. In 1894, B was how many times as old as A ? n6 Chapter Two. 59. From the sum of 18^ and 25£ take their difference. 60. If 2f acres of land cost $ 220, what will be the cost of 17 $ acres? Note. — Indicate the operations, and cancel. 61. A can do a piece of work in 6 days, B can do it in 6 days, C can do it in 6 days. How long will it take all three working together ? 62. Find the value of 1 f t£*M . 63. A man sold a horse for } of its cost, losing $40. What did the horse cost him ? 64. I have an oblong piece of land which is 96 feet long and 72 feet wide. There are three gateways; one is two feet wide, one is three feet wide, and the other is four feet wide. How many feet of fence will it take to go around the field? 65. Add: $83.34; $67.58; $50.37; $62.50; $35.75; $62.50; $35.75; $63.81; $67.59; $86.37; $37.50; $15.09; $57.32; $49.63. 66. A boy bought a suit of clothes for $21, boots for $3.50, overcoat for $15, and gloves for 50 £ Paid for these things in work at $1.25 per day. How many days did he work? 67. If $36.53 will buy 6£ yards of cloth, how much will ■J- yard cost ? 68. If two quarts of peaches cost 25^, what will half a bushel cost? 69. How many geographies at 90^ apiece can be bought for $54? 70. Find the least common multiple of 6, 24, 32, 48, 96. 71. Add: 87.5; 7004.3; 500.004; 21,090; 5040.29. Review. 117 72. Spent $290 for horses, $286.75 for carriages, $150.80 for harness, and $12.75 for blankets. Gave 4 fifty-dollar bills and 2 one-hundred-dollar bills. What did I still owe ? 73. How many bushels of oats will a span of horses eat in 4 weeks, if they eat 24 quarts a day? 74. How many bottles, each holding \ pint, will it take to hold 725 gallons and 2 quarts of oil ? 75. How many pounds of rice at 12^ a pound, will pay for 4 bushels 2 pecks of nuts at 8^ a pint ? 76. A man had $ 600. He bought a horse for $ 225, a carriage for $ 190.12, and a harness for $ 40.76. He then gave away £ of what he had left. What did he still have? 77. Find the greatest common divisor of 18, 24, 36. 78. The least common multiple of 12, 20, and 30. 79. Find the cost of 18,756 feet, of lumber at $30 per 1000 ft. 80. A field is 14.25 rods long by 7.4 rods wide. What is- its area in square rods ? 81. A rod is 16.5 feet; how many feet are there in 24 rods ? How many rods are there in 231 feet ? 82. How many marks are there in $100? (A mark is- equal to 23.8 cents.) 83. Add 3 and 4 tenths, 96 thousandths, 100 and 5 thou- sandths, 27 hundredths. 84. From 2700 take 27 hundredths. 85. Multiply 8 and 4 tenths by 9 and 25 hundredths. 86. Divide 96 and 75 hundredths by 322 and 5 tenths. 87. A load of hay, at 75 cents per 100 pounds, cost $13.98. What was the weight of the hay ? xi8 Chapter Two. 88. The circumference of a circle is 3.1416 times the diameter. How many inches in the circumference of a circle whose diameter is 20 inches ? 89. Show by a diagram the number of pieces of wire # yard long that can be made from 4 yards of wire. 90. Show by a diagram that three-fourths of 1 is equal to one-fourth of 3. 91. If two-thirds of a yard of material will make an apron, how many aprons can be made from two yards ? Show by a diagram. 92. A boy paid 6 cents for three-eighths of a pie. What would be the cost of the whole pie at the same rate? Make a drawing. 93. Seven-eighths of an acre of land is sold for $140. What is the price of an acre? CHAPTER III. PAGES Decimals 119 to 132 Notation and Numeration, Reduction, Addition, Sub- traction, Multiplication, Division. United States Monet 132 to 133 Denominate Numbers 133 to 139 Reduction, Addition, Subtraction, Multiplication, Division (two denominations). Measurements 139 to 144 Areas of Rectangles, Areas of Right-angled Triangles. Bills 144 to 145 Percentage 145 to 147 Interest 148 to 152 Review of Simple Numbers and Fractions . . 152 to 162 Sight Approximations, Special Drills, Cancellation, Ratio, Short Methods, Review Fractions. Miscellaneous Problems 162 to 172 Oral and Written. DECIMALS. 185. Preliminary Exercises, 1. Write seven tenths as a common fraction. As a decimal. 2. Write three hundredths as a common fraction. As a decimal. 3. Write thirty-one thousandths as a common fraction. As a decimal. 119 ISO Chapter Three. 4. Kead the following : .3 .09 .043 .17 .007 .241 5. Write each of the foregoing decimals as a common fraction. 186. Notation and Numeration of Decimals. 1. 7 tenths, or T 7 7 , is written .7. 2. 3 hundredths, or -j-J^, is written .03. 3. 53 hundredths, or ^j-, is written .53. 4. 9 thousandths, or Tir Vu"> * s written .009. 6. 19 thousandths, or j^fo, is written .019. 6. 419 thousandths, or ^j^, is written .419. 7. 67 ten-thousandths, or l0 6 7 00 , is written .0067. 8. 1031 hundred-thousandths, or y^nHBiF' * s written .01031. Note. — In the foregoing examples, it will be observed that the num- ber of places to the right of the decimal point is equal to the number of ciphers in the denominator of the corresponding common fraction. 187. Write the following as decimals : 1. 314 ten-thousandths. Since y^^ has a denominator containing four ciphers, the decimal roust have four places ; a decimal cipher must be written after the decimal point. Ans. .0314. To write a decimal, write the numerator, and from the right, point off as many decimal places as there are ciphers in the denominator, prefixing decimal ciphers, if necessary. Note. — Ciphers between the decimal point and the first significant figure of the numerator are called decimal ciphers. Decimals. 121 2. 217 hundred-thousandths. 3. 83 hundredths. 4. 7 millionths. 5. 345 thousandths. 6. 27 ten-thousandths. 7. 325 and 7 thousandths. Ans. 325.007. This is called a mixed decimal, which consists of an integer and a decimal. 188. The word and is used in reading mixed numbers or mixed decimals to separate the integer from the common fraction or the decimal. 8. 42 and 56 hundred-thousandths. 9. 150 and 62 millionths. 10. 489 and 3 hundredths. 189. Eead the following: 1. .0346. Since there are four decimal places, the denominator is 1 with four ciphers, 10000. Ans. 346 ten-thousandths. 2. 654.15 6. 25.006347 3. .000209 7. 3.259 4. 60.0207 8. .002468 5. 684.007 9. 200.0035 200.0035 read as 200 and 35 ten-thousandths might be mistaken for 235 ten-thousandths. It should be read 200 units and 35 ten-thou- sandths, or 200 whole number and 35 ten-thousandths. 10. 1000.0006 12. 2300.00021 11. 300.075 13. 400.000007 122 Chapter Three. 190. Changing Common Fractions to Decimals. Eeduce -£% to a decimal. ■fc means 3 -4- 32. Performing the indicated division, we obtain the quotient .09375. -fa = .09375, Ans. Divide the numerator, ivith the necessary ciphers annexed, by the denominator. The number of decimal places in the quotient will be equal to the number in the dividend. .09375 Eeduce to decimals 1. "T017 2. A 3. A 4. H 5. H 6. A 7. sort 8- * y. 4000 10. 2 00 11. H 12. TT5" 13. ¥ 14. « 32)3.00000 288 120 96 240 224 160 160 15. 250" 16. F2T 17. W 18. T% 19. T5~8" 20. "ST"? 21- rrfcr 191. Changing Decimals to Common Fractions. What is the denominator of a decimal fraction ? What prime numbers are contained in 10 ? What are the only factors of 10 ? The prime factors of 100 ? Of 1000 ? Can yoVg he reduced to lower terms ? Why ? Can jfo be reduced to lower terms ? Why ? Can y^jj^rr be reduced to lower terms ? How can we tell by merely looking at a decimal whether or not it can be reduced to a common fraction of lower terms ? 192. Written Exercises. . Reduce the following to common fractions — lowest terms. Do not find the greatest common divisor. 1. Reduce .0064 to a common fraction — lowest terms. •0064 = T &V* = rib = vfc, -4ns. Decimals. 123 2* Reduce .039 to a common fraction. •039 = xfjyi Ans. This cannot be reduced to lower terms, since 39 is not divisible by 2 or 5. 3. Reduce .900 to a common fraction — lowest terms. tW(5 = tVff = tV Ans. Omit the decimal point. Write in the form of a common fraction, and reduce to lowest terms. Ciphers at the right of a decimal cancel ciphers in the denominator ; they do not, therefore, affect the value of the decimal, and they should be omitted. 193. Reduce to common fractions : 1. .0075 8. .37500 15. .0009 2. .36 9. .144 16. .816 3. .0275 10. .0006 17. .15625 4. .44 11. .27 18. .0375 5. .03125 12. .027 19. .00625 6. .486 13. .00365 20. .096 7. .3750 14. .96 21. .326 ADDITION OF DECIMALS. 194. Add the following, reducing the common fractions to decimals. 1. 18£ + 9.084 + 25^ + 163 + 2.09 + .0975 18.75 9.084 Write the decimals so that tenths, hundredths, etc., 25.05 stand in the same column, etc„ 163. 2.09 .0975 124 Chapter Three. Write the numbers so that decimal points stand in a column. Add as in integers, and place the point in the sum directly under the points above. 2. 275^ + 58.64 4 8.6796 4 30J- 4 8f 4 99 3. 84 1 ^ + 93 T ^4-3 I i^ + TlHir + 684.1 + i 4. 250 + 1875.93 4- Iff + A + 608.94 + .0005 5. 8.6796 + 96.8 + 18f + 34^ + 1876 6. 40^ + 7.2832 4 86.3 4 128.46 4 2^ 7. 540 41.32 4-576 4 1^ + 68^ 4 395£ 8. 5.308 4 .25 4 567.8 + 8.4825 4 49.795 + 8^ 9. 7.08 + 23.04 4 8^ 4 .348 + 3^ 4. 7.00019 10- 8^^4-8^4 507 + 28^4 6.8819 SUBTRACTION OF DECIMALS. 195. Give answers in decimals : 1. 275.3 -87 A 275.3 Arrange the decimals as in addition, tenths under ^~ ^ . tenths, etc. ^ nn \„ . 188.26 Ans. Write the numbers so that the decimal point of the subtra- hend is directly under the decimal point of the minuend; sub- tract as in integers, and place the point in the remainder directly under the points above. 2. 387f - 99.0127 7. 2345-345^- 3. woo -T^n 8. 168^-54.8759 4. 62.365-48| 9. 618.42 -;576J 5. 198}- 13.6431 10. 1847H-344rfo 6. 24A-9rtt* 11. 622.5-6.243 Decimals, 125 196. Oral Problems. 1. Reduce -fa to a decimal. 2. Express the decimal .3 J as a simple fraction. 3. What decimal of a ton is 125 pounds ? 4. One hundred fifty marbles are divided among a certain number of boys. Each receives 12 and there are 6 remaining. How many boys are there ? 5. Express the decimal .62^ as a simple fraction. 6. What decimal of a peck is 7 quarts ? 7. If 8 men can do a piece of work in 6 days, in how many days can 4 men do it ? 8. If Maria spends $ .75 a day, in how many days will she spend $9? 9. If you had 3J oranges to divide among your friends, giving each \ of an orange, to how many friends would you give? 10. -J- of 14 is -J- of what number ? 11. Change .75 yards to feet and inches. 12. At 16|^ a yard, what will 12 yards of ribbon cost ? 13. At 80^ a pound, what do 4 ounces of tea cost ? 14. If I have 12 yards of ribbon, to how many girls can I give f of a yard each ? 15. A boy lives 10^- rods from his school. How far does he walk in a day to attend two sessions of school ? 197. Written Problems. 1. In the written number 54,372, the value expressed by the 5 is how many times the value expressed by the 2 ? 2. Find the sum of two and twenty-five thousandths, five and twenty-seven ten-thousandths, forty-seven and one hundred twenty-six millionths, one hundred fifty and seven ten-millionths. 126 Chapter Three. 3. In a mass of alloy weighing 291.42685 pounds, there were found 40.0921 pounds of silver, 160.09090 pounds of copper, 22.002 pounds of iron, and .426900 pounds of zinc. The remainder was lead. What was the weight of the lead ? 4. How many bushels of oats at f of a dollar a bushel will pay for f of a barrel of flour at $ 5.40 a barrel ? 5. Add 3.684; 19.5; .00875; 15,863.625; 8.7; and 100.4875. 6. Change to a common fraction in its lowest terms .009375. Change -fe to a decimal. 7. If f pound of tea costs $■$■, how many pounds can be bought for $7.50? 8. Change to common fractions .0075 and .625. 9. Change to decimals ^-, • 2 - 9 -, and 5 J, and add the results. 10. Reduce to common fractions, and then find the sum of the common fractions: .12^-, .3^-, .16f. 1 1 . Add three hundred seventy-six ten-thousandths, forty- five hundred-thousandths, five hundred sixty-eight thou- sandths, fourteen and fifteen hundredths. 12. At 24 cents per gallon, what will be the cost of 16 gal. 3 qt. of milk ? MULTIPLICATION OF DECIMALS. 198. Give answers in decimals : 1. Multiply .000486 by 29.5. Place the units' figure (9) of the multiplier under the last figure (6) of the multiplicand. 486 millionths multiplied by 2 tens gives a prod- uct of 972 hundred-thousandths, or .00972 ; place the right-hand figure (2) of this product under the 2 of the multiplier, etc. — 00Q79 The result, .0143370, contains seven decimal places, -w^i* which is equal to the six in the multiplicand plus the one ^374 in the multiplier. Rejecting the unnecessary cipher at 2430 the right, the product is .014337, Am. .0143370 Decimals. 2. Multiply 29.5 by .000486. The units' figure of the multiplier may be considered as zero. Ans. .014337. 127 29.5 0.000486 .01180 2360 1770 .0143370 Multiply as in whole numbers, and from the right of the product point off as many decimal places as there are decimal places in both factors. Multiply : 1. 24.75 x 3.02 6. 1.876 x 34 2. 98| x .00046 7. 3.48 x 4.8665 3. 148^x12.5 8. .43J x 1A 4. 380^- x .012 9. 192.38 x .238 5. .09375x1.48 10. 26.4 x .016 DIVISION OF DECIMALS. 199. 1. Divide 7.345 by .29. Make the divisor a whole number by mov- ing the decimal point two places to the right, which multiplies the divisor by 100 ; and make a corresponding change in the dividend. Di- viding 734.5 by 29 gives a quotient of 25.3275+. Since the quotient is to be limited to three decimal places, 8 followed by a minus sign is substituted for the 7, to indicate that the fourth decimal figure is at least 5. 25.327 /29)7/34.500 58_ 154 145 95 5L 80 58_ 220 203 17 Ans. 25.328- i*8 Chapter Three. 2. Divide 753 by 4.18. Kemoving the decimal point in the divisor two places to the right multiplies the divisor by 100. Annex two ciphers to the dividend. As the fourth decimal figure in the quo- tient is greater than 5, the 3 is changed to a 4, followed by a minus sign. Arts. 180.144 - 3. Divide .8756 by 4326. The decimal point in the quotient is placed over the new decimal point in the dividend, the necessary decimal ciphers being sup- plied. A + sign is placed after the last quotient figure to show that the next quo- tient figure is less than 5. 180.143 4/18.)753/00.000 418 3350 3344 60.0 41.8 18.20 16 72 1480 1254 226 Arts. .0002024 + 4326).8756000 8652 10400 8652 17480 17304 176 Make the divisor a whole number by removing the decimal point, and make a corresponding change in the dividend. The number of decimal places in the quotient will be equal to the number in the dividend as changed. 200. Written Exercises. Divide : 1. 4.054 -j- 18.25 10. 62.478 + 4279 2. 123.5 -j- 384 11. 346.25 -f- 64.8 3. 471 -*- 5.325 12. 9.1342 -4- 208.3 4. .3126 -h .0134 13. 1784 -f- 29.57 6. 12.345 -r- .0047 14. 343.71 -f- 1.127 6. .8756 -*- 4.322 15. 83.087 -5- 5.37 7. 8 -f- 122 16. 137.84 -5- 7.91 8. .3678 -*- .9125 17. 38.9008 -*- .523 9. 48.45 -*- .089 18. .81074 h- .0091 Decimalso 129 201. Solve by short division: 1. Divide 18.756 by 3000. Cancel the ciphers in the divisor, thereby dividing it by 1000. Move the decimal point in the dividend three places to the left, which divides it by 1000. Place the decimal point in the quotient under the new decimal point in the dividend. 3000 ).O18/756 .006252 Ans. 2. 48.36-5-4000 11. 48.64-5-200 3. .4824-5-12000 12. .00531-5-90000 4. 11.011-5-700 13. 96.51-5-60 5. 3.6504-90 14. 87.5^-500 6. 45.63-5-1500 15. 183.275-5-10000 7. 130.13-5-1100 16. 1.7632-5-1600 8. .8712-5-60 17. 1.5639-5-130 9. 3.075-5-5000 18. 614.4-5-120 10. .07056-5-140 19. .8008-7000 202. Perform indicated operations. Change the divisor to a whole number, making corresponding change in the dividend. Cancel. 2. 7 34.2 x/OT tm .249 x 3.92 .098 .083 x .72 288 .6876 x .27 .081 234 .001 239.4 5. ffi/ff x -#3--.234 I&0 6. 7. 3.1416 x 2.3 .7854 7.72 x 65 19.3 450 x 23.8 1.19 130 Chapter Three. 34.3 x 8.1 2.75 x .801 * .49x100 ' 1.1x6 .576 x 6.3 .306 x 8.75 ' 14.4x25 ' .9x68 203. Eeduce to common fractions — lowest terms. 1. Eeduce .3^ to a common fraction — lowest terms. .3£ is a complex decimal ; that is, a decimal and a common fraction written together. It may be written as the complex fraction ^3, which means S\ -h 10. Note. — A complex fraction is one which has a fraction in the numerator or in the denominator or in both. 2. Eeduce .006 \ to a common fraction — lowest terms. .006* = . 00625 = T ^b; dividing both terms by 25, we get jffo ; dividing both terms by 25, we get T ^, Ans. 3. .33J 6. .01£ 9. .04£ 4. .16| 7. .06| 10. .76ff 5. .142^ 8. .833| 11. .037£ 204. Oral Exercises. 1. Divide 6 by .03. 2. f is what part of 2 ? 3. What is the product of one hundred by one-hundredth? 4. Subtract 25 thousandths from 5. 5. What will 150 pounds of coffee cost at the rate of 3 pounds for 50 cents ? 6. What will be the cost of 3 pecks of cherries at 2 cents a pint? Decimals. 131 7. Divide -§ by f . 8. At 3 oranges for 5 cents, what will be the cost of 4 dozen oranges ? 9. If a man walks ^ of a mile in 10 minutes, bow far can be walk in an hour and a half ? 10. A woman bought 12 yards of cloth at 70^ a yard ; she paid $ 5 in cash, and the rest in butter at 20^ a pound, How many pounds of butter did she give ? 205. Written Exercises. 1. Divide the sum of .736 and 1.2854 by their difference= 2. Divide .1 by .2, and .35 by 35, and find the product of the quotients. 3. Eeduce -^fa to a decimal, and divide it by .3125. 4. Divide .12096 by .032. 5. Multiply .00273 by 3000.456, and divide the .product by .08. 6. Divide 12.3125 by .000625. 7. Divide 51.5 by 412, and 412 by 51.5. 8. Multiply 31.5 by 27.9, and divide the product by 9.765. 4 9t 9. Eeduce ^=^-. 3-H 10. Find the value of ' 0Q21 * 3004 . .024 11. What will be the duty on 175 kilograms of wool at 33 cents per pound ? (1 kilogram = 2.2046 pounds.) 12. How much is the fraction f increased or diminished when 2 is added to each of its terms (numerator and denom- inator) ? 132 Chapter Three. 13. Find the cost of 360 meters of cloth at $1.10 per yard (1 meter = 39.37 inches). 14. Find the cost in United States money of 386 hats at 24 francs each (1 franc = 19.3 cents). 15. Find the cost in United States money of 480 meters of cloth at 1.10 marks per meter (1 mark = 23.8 cents). 16. A merchant bought 30 pieces of cloth, each contain- ing 41.6 yards, for $3,875 per yard, and 25 pieces of 36.8 yards each, for $ 4.125 per yard. He sold the entire lot for $ 3.96 per yard. How much did he gain or lose ? 17. An importer received a box of chemicals weighing 122 grams, each gram containing 15.432 English grains, on which he paid a duty of $.05 per grain. What was the amount of duty ? 18. A dealer exported 374.319 bushels of corn, receiving in exchange coal at the rate of 1 ton of coal for 15.124 bushels of corn. How much coal did he receive? 19. .75 is what part of 3.25 ? 20. Keduce .005025 to a common fraction. UNITED STATES MONEY. 206. Written Exercises. 1. Find the cost of 24,400 bricks @ $ 6.25 per M. M means 1000. 24,400 = 24.4 M. Since the cost per thousand is $6.25, 24.4 thousand will cost 24.4 times $6.25. 2. 760 pounds of hay @ 95 cents per cwt. (100 pounds) ($.95x7.6) 3. 48,600 laths @ $ 2.80 per M. 4. 39,250 stamped envelopes @ $21.30 per thousand. 6. 1875 pounds of straw @ 68 cents per cwt. Denominate Numbers. 133 6. 108,745 Philadelphia bricks @ $22 per M. 7. 14,860 oranges @ 75^ per hundred. 8. 2376 eggs @ 13J^ per dozen. 9. 4500 cigars® $35 per M. 10. 28 dozen wax candles @ $13.50 per gross (144). Solve by cancellation where possible : 1 1 . 38,648 pounds of wheat @ 90 f per bushel (60 pounds). ' Since there are 60 pounds in a bushel, 38,648 pounds = 8.09 ^^ bushels. At 90 cents per bushel, the cost is $ '^ x38648 , etc. 60 60 Note. — In cancelling, be careful not to strike out a cipher in 60 and one in .90, without inserting a decimal cipher. 12. 18,964 pounds of coal @ $5 per ton (2000 pounds). 13. 48,576 pounds of oats @ 36/ per bushel (32 pounds). 14. 69,104 pounds of rye @ 91-J-^ per bushel (56 pounds). 15. 74,816 pounds of corn @ 48^ per bushel (56 pounds). DENOMINATE NUMBERS. 207. Written Exercises. 1. Change 12 pounds and 9 ounces to ounces. Since there are 16 ounces in 1 pound, in 12 16 oz. pounds there are 12 times 16 ounces, or 192 ounces. i In 12 pounds 9 ounces, there are 192 ounces + 9 ounces, or 201 ounces. \ f * D - jj oz " The work may be arranged in this way. Above 201 oz. the ounces, write the number of ounces in a pound, viz. 16. Multiply 16 ounces by 12, adding in the ^ ns ' 201 oz. 9 ounces. 134 Chapter Three. Change : 1. 20 rods and 3 yards to yards. 2. 2 miles to yards. 3. 3 days and 17 hours to hours. 4. 24 minutes and 15 seconds to seconds, 5. 8 tons and 1675 pounds to pounds. 6. 43 gallons and 8 quarts to quarts. 7. 75 gallons to pints. 8. 19 bushels and 3 pecks to pecks. 9. .03125 ton to pounds and ounces. 10. -J yard to feet and inches. 208. "Written Exercises. Change : 1. 975 ounces to pounds and ounces. 2. 396 inches to yards. 3. 517 hours to days and hours. 4. 1694 seconds to minutes and seconds. 5. 9314 pounds to tons and pounds. 6. 987 pints to gallons, quarts, and pints. 7. 1485 quarts to pecks and quarts. 8. 185 pecks to bushels and pecks. 9. 840 hours to weeks. 10. 12 hours to the fraction of a week. 11. 28 inches to the fraction of a yard. 12. 10 ounces to the decimal of a pound. 13. 3 quarts to the decimal of a bushel. Denominate Numbers. 135 209. Written Exercises. Add: 1. 13 lb. 6 oz. 10 oz. +9 oz. + 6 oz. = 25 oz. = 1 lb. 9 oz. 5' lb. 9 oz. Write 9 ounces and carry 1 to column of 25 lb. 10 oz. pounds. Ans. 44 lb. 9 oz. 2. 19 yd. 1 ft. 2 ft. 3 yd. 1 ft. 3. 5 min. 30 sec. 11 min. 25 sec. 9 min. 18 sec. 4. 4 ft. 9 in. 2 ft. 6 in. 7 ft. 7 in. 6. 18 gal. 3 qt. 9 gal. 1 qt. 2 qt. 210. Subtract: 1. 81b. 4 lb. 7 oz. 2. 15 yd. 1 ft. 9 yd. 2 ft. 3. 17 hr. 9 hr. 50 min. A. 1 yd. 1 ft. 1 in. 2 ft. 9 in. 5. 25 gal. 1 qt. 6 gal. 3 qt. 6. 7. 11 bu. 3 pk. 6 bu. 2 pk. 2pk. Ipk. Ipk. 6qt. 7qt. 5qt. 3 wk. 6 wk. 1 wk. 5 da. 6 da. 3 da. 11 T. 4T. 165 lb. 983 lb. 1756 lb. Change 8 lb. to 7 lb. 16 oz. 16 oz. — 7 oz. = 9 oz. 7 lb. - 4 lb. = 3 lb. Ans. 3 lb. 9 oz. 6. 89 bu. 2 pk. 67 bu. 3 pk. 7. 3 pk. 2 qt. 2 pk. 7 qt. 8. 11 wk. 1 da. 9 wk. 5 da. 9. 5T. 896 1b. 1984 lb. 136 Chapter Three. 211. Multiply: 1. 12 lb. 7 oz. x 3 3 times 7 ounces are 21 ounces, or 1 pound 6 ounces. Write 6 ounces. 3 times 12 pounds are 36 pounds, and 1 pound to carry are 37 pounds. Ans. 37 lb. 5 oz. 2. 3 hr. 10 min. x 7 7. 7 min. 18 sec. x 10 3. 4 T. 985 lb. x 11 8. 9 gal. 3 qt. x 2 4. 7 bu. 3 pk. x 9 9. 2 ft. 9 in. x 8 5. 3 wk. 4 da. x 4 10. 1 yd. 1 ft. 6 in. x 6 6. 4 yd. 1 ft. x 5 11. 3 yr. 4 mo. x 7 212. Divide: 1. 9 1b. 2oz. -s-2 \ of 9 pounds is 4 pounds and 1 pound remainder, ^q •,, « or 16 ounces. Add to this 2 ounces, giving 18 ounces ' . * _ 4 lb. 9 oz. for the dividend. \ of 18 ounces is 9 ounces. Ans. 4 lb. 9 oz. 2. 31 gal. 2 qt. -f- 9 7. 19 ft. 2 in. -- 10 3. 19 hr. 21 min. --3 8. 34 T. 936 lb. -- 4 4. 26 bu. 1 pk. 4-5 9. 17 wk. 1 da. 4-6 5. 41 min. 44 sec. 4- 8 10. 52 yd. ft. 9 in. 4- 11 6. 18 yd. 2 ft. 4- 7 11. 23 yr. 4 mo. 4- 7 213. Divide: 1. 18 lb. 4 oz. by 4 lb. 9 oz. 18 lb. 4 oz. = 292 oz. 4 lb. 9 oz. = 73 oz. 292 oz. -r- 73 oz. = 4, Ans. Note. — Change the divisor and the dividend to the same denomi- nation. The answer is an abstract number. Denominate Numbers. 137 2. 16 yd. by 2 yd. 2 ft. 3. 51 hr. 36 min. by 6 hr. 27 min. 4. 47 min. 42 sec. by 5 min. 18 sea 5. 84 yr. 7 mo. by 12 yr. 1 mo. 6. 19 da. 3 hr. by 2 da. 3 hr. 7. 3 mi. 40 rd. by 125 rd. 8. 103 T. 808 lb. by 8 T. 1234 lb. 9. 52 gal. 2 qt. by 3 gal. 2 qt. 10. 68 bu. 1 pk. by 5 bu. 1 pk. 11. 30 ft. 8 in. by 1 ft. 11 in. 12. 52 yd. 9 in. by 4 yd. 2 ft. 3 in. 13. 51 wk. 3 da. by 2 wk. 6 da. 214. Oral Problems. 1. What will be the weight of 16 hams that average 10 lb. 5 oz. each ? 2. From a chest of tea containing 54 pounds there were sold 27 lb. 7 oz. How many pounds remain ? 3. Seven bushels of potatoes are divided among 8 per- sons. How many pecks and quarts does each receive ? 4. How many square inches in the surface of a sheet of paper measuring 11 inches by 13 inches ? 5. How many feet and inches in £ yard ? 6. What decimal of a pound is 14 ounces ? 7. A man buys a bushel of hickory nuts. After he sells 2 pk. 4 qt., what fraction of the bushel has he left ? 8. A dealer puts 30 gallons of milk in cans holding 1 qt. 1 pt. each. How many cans does he fill ? 9. At $ 24 per month, how much rent will a man pay in 1 year and 5 months ? 138 Chapter Three. 10. 75 hundredths of a pound is how many ounces? 11. How many feet in 5 rods ? 12. 7 qt. 1 pt. of milk is divided among 5 people. How many quarts and pints does each receive ? 13. What fraction of 2 lb. 3 oz. is 1 lb. 4 oz. ? 14. Three-eighths of a ton is how many pounds ? 15. Change 9 hr. 36 min. to the fraction of a day. 215. Written Problems. 1. 32 hams weigh 464 pounds. What is the average weight ? 2. 595 gallons of oil are put into 14 barrels. How many gallons and quarts does each contain ? 3. If there are 42 gallons and 2 quarts in a barrel of oil, how much oil will there be in 15 barrels ? 4. A piece of cloth containing 57 yards is divided equally among six persons. What is the length of each one's share ? 5. How many minutes in a day? 6. July 1 is the last school day. How many days' vacation will there be, if school begins September 6 ? 7. How many hours and minutes are there from half- past 3 Saturday afternoon to a quarter before 9 Monday morning ? 8. How many steps, 2 ft. 6 in. long, must a man take in walking 1200 feet ? 9. A man owns a plot of ground 420 feet long, 240 feet wide. How many rods of fence will be required to enclose it? 10. A train goes from Jersey City to Washington, 228 miles, in 4 hr. 12 min. How many miles an hour does it travel ? How long does it take the train to go one mile ? Measurements. 139 11. On Monday a boarding-house uses 3 gallons 2 quarts of milk ; on Tuesday, 4 gallons ; on Wednesday, 3 gallons 1 quart; on Thursday, 4 gallons 2 quarts; on Friday, 6 gallons ; on Saturday, 5 gallons 2 quarts ; on Sunday, 3 gal- lons. How much is used during the week, and what is the average per day ? 12. June 21 the sun rises at New York at 4.23 a.m. and sets at 7.40 p.m. How long is the night ? 13. From 3£ bushels take 3 pecks. 14. What is the number of rods in the perimeter of a field 206 ft. 3 in. wide and twice as long ? MEASUREMENTS. 216. Written Exercises. How many square inches in each of the following rec- tangles ? First change each dimension to inches. 1. 42 in. by 36 in. 6. 9 ft. by 11 ft. 2. 71 in. by 18 in. 7. 27 in. by 30 in. 3. 3 ft. 1 in. by 4 ft. 2 in. 8. 65 in. by 92 in. Note. —37 in. by 50 in. 9. 7 ft. 3 i n . by 2 yd. 4. 5 ft. 3 in. by 6 ft. 4 in. 10> 3 yd by 6 ft 6 in 5. 12 ft. by 18 ft. (108 in. by 78 in.) 217. How many square feet in each of the following rec- tangles ? First change each dimension to feet, or to feet and a fraction. 11. 18 ft. by 24 ft. 15. 31 ft. by 4 ft. 12. 36 in. by 4 ft. 16 - 3 ft. by 1J yd. (3 ft. by 4 ft.) 17. 42 in. by 4 ft. 13. 6 yd. by 8 yd. 18. 25 ft. by 17 ft. 6 in. (18 ft. by 24 ft.) 19. 42 in. by 48 in. 14. 1 yd. by 48 in. 20, 13 yd. by 15 yd. 140 Chapter Three. 218. How many square yards in each of the following rectangles ? Change each dimension to yards, or to yards and a fraction. 21. 18 yd. by 25 yd. 26. 36 yd. by 24 in. 22. 15 yd. by 1 yd. 1 ft. 27. 17 ft. 6 in. by 32 in. 23. 27 ft. by 36 ft. 28. 22 ft. 9 in. by 18 in. 24. 54 ft. by 2 ft. 6 in. 29. 108 in. by 90 in. 25. 24 yd. by 27 in. 30. 180 ft. by 54 in. 219. Oral Exercises. 1. If a table is 3 yards long and 2 yards wide, how many square feet in it ? 2. If it takes 24 yards of carpet, a yard wide, to cover a floor, how many yards f yard wide will be needed for the same floor ? 3. How many square inches in \ of a square foot ? 4. A room is 21 feet long and 18 feet wide. What will it cost, at 5 cents per yard, for a strip of moulding around the walls ? 5. How many square yards of carpet would be needed for the floor of the above room ? 6. A field is 40 rods long and 26 rods wide. What is the distance around it ? 7. What will it cost to carpet a room 18 feet long, 15 feet wide, at 75 cents per square yard ? 8. What is the cost of fencing a lot 24 rods long by 20 rods wide, at $ 1.12 J per rod? 9. My field is 100 rods long and 75 rods wide. How much is it worth at $ 2 a square rod ? How much will it cost to fence it at $ 1 a rod ? 10. How many yards of fence will be required to enclose a rectangular field 98 yards long and 50 yards wide ? Measurements. 141 220. Written Problems. Make a diagram in each case : 1. A lot 25 feet by 100 feet has on it a house 25 feet by 55 feet. How many square feet are there left for a yard ? 2. How many square feet are there in the floor of a room 24 feet long, 18 feet wide ? 3. How many square yards are there in the ceiling of the same room ? 4. Find the number of square yards of plastering needed for the end wall of a room 18 feet wide, 9 feet high, after deducting for two windows each 6 feet high, 4£ feet wide. 5. How many square yards of plastering will be needed for the opposite wall of the same room, 18 feet wide, 9 feet high, after deducting for a door 7J feet high, 6 feet wide ? 6. Calculate the number of square yards of plastering needed for two side walls of a room 24 feet long, 9 feet high, after deducting for a fireplace 6 feet square on one side. 7. A house 30 feet by 60 feet, with an addition 15 feet square, is built upon a lot 100 feet square. How many square feet of ground are covered by the building ? How many square feet remain for a garden ? 8. Measure the top of a brick and calculate the number of square inches in its surface. How many square inches in the surface of the bottom of the brick? Measure one side, and calculate its surface. How many square inches are there in the surface of the opposite side ? How many square inches in each end ? 9. Measure a crayon box, and calculate the number of square inches in each face. 142 Chapter Three. 10. Calculate the number of square feet in the floor of the classroom. In the ceiling. In each side wall. In each end wall. 11. What will it cost to put moulding around a room shaped like the drawing, allowing 3 inches on every corner for matching, the moulding being worth 5f ^ a foot? 10 ft. • £ -«*< 6 ft. € 05 22 ft. 12. The circumference of a circle is 3.1416 times the diameter. What is the diameter of a circular track 1760 yards in circumference ? Find to two places of decimals. 13. Show the difference between 2 square inches and 2 inches square. 14. How many paving tiles 6 inches square are needed to cover a floor 18 feet long, 10 feet wide ? 15. How many flagstones, each 4 feet long and 2 feet wide, will be needed to lay a crossing 32 feet long and 6 feet wide ? What will be the cost of them at the rate of $50 for 100 stones? Measurements. 143 AREAS OF RIGHT-ANGLED TRIANGLES. 221 . Preliminary Exercises. The square shown in the diagram is divided into two parts by a diagonal. One side of the square measures 10 feet. 1. Mark in each triangle its area. Square. Eectangle. 2. Divide a rectangle 20 feet by 12 feet into two parts by a diagonal. Mark in each triangle its area. 3. Draw a right-angled triangle 3 inches by 4 inches. Calculate its area in square inches. 4. How many square yards in the sur- / jj face of a right-angled triangle whose base measures 30 feet, and whose perpendicular measures 224 feet ? / n £ 222. Written Exercises. Find the area in square feet of the following right-angled triangles. (Change each dimension to feet.) 1 . Base 20 yards, perpendicular 30 feet. Area = 1 square foot x £ (60 x 30) = 900 square feet, Ans. Tlie number of square feet in the area of a right-angled triangle is equal to one-half the product of the number of feet in the base by the number of feet in the perpendicular, 144 Chapter Three. 2. Base 16 inches, perpendicular 3 feet. 3. Base 30 inches, perpendicular 1 yard. 4. Base 3 feet 6 inches, perpendicular 5 feet. 5. Base 2 yards 1 foot, perpendicular 1 yard 9 inches. 6. Base 50 yards, perpendicular 36 yards. 7. Base 112J- feet, perpendicular 30 yards. 8. Base 90 inches, perpendicular 2 feet. 9. Base 12^- yards, perpendicular 13^ yards. 10. Base 1 rod, perpendicular 1\ feet. 11. Base 33 \ feet, perpendicular 18 feet 6 inches. BILLS. 223. Philadelphia, Sept. 24, 1905. Mr. William J. Hurley, To John J. Petit & Son, Dr. To 50 lb. Pipe 5\t To 8 Faucets 75$ To 1 Sink To 3^ days' Labor 94.7S 75 $ 1. Copy and complete the above bill. 2. Albert Janson has done 3J days' work, @ $ 3.50 per day, for Ephraim Whitlock. He charges for 850 feet lumber, at $ 2 per hundred; 5 pounds of nails, at 9^ per pound; 3 locks, @ 50^ ; 2 bolts, at 10j*. Make out his bill. 3. A gardener furnishes 3 rose bushes, at 75^; 4 grape- vines, at 50^ ; 11 fuchsias, at 30^ ; 25 pansies, at 10^. He charges $3.25 per day for 2\ days' labor. Make out his bill. Percentage. 145 4„ An upholsterer charges $ 3 per day for repairing some furniture. He supplies 6 pounds of hair, at 50^ per pound ; 17 yards of plush, at $ 1.75 per yard; 3 papers of tacks, at 10^; cord, gimp, etc., 47^. He works 4 days. Make out his bill. Note. — The foregoing bills are for work done and materials sup- plied. Notice how the heading differs from those in Arts. 103 and 173. 5. Make out and receipt a bill for four articles bought to-day by John Harrigan from Metz and Fagan, grocers (Art. 103). 6. Make out a bill containing ten items bought by Mrs. A. S. Jacobs, at different times during October, 1905, from Frederick Loeser & Co., dealers in dry goods (Art. 173). 7. Make out a bill for labor done and materials furnished by Joseph Minew, gardener. PERCENTAGE. 224. Per cent means hundredths. Six per cent means six hundredths, jfo, or .06. It is writ- ten 6%. 225. Oral Exercises. 1. What is 6% of 200? 6% means jfo. To find 6% of 200, we multiply 200 by ^fo, or 200 x .06. Arts. 12. 2. What is yffr of 300 ? 6. 6% of 150 3. Find .06 of 400 7. 6% of 250 4. 6 per cent of 500 8. 6% of 125 5. 6% of 50 9. 6• 10 <$- = 2 gal. 2 qt. Write 2 quarts in the column of quarts. 3 times 4 gal. = 12 gal. ; 12 gal. + 2 gal. to carry = 14 gal. Ans. 14 gal. 2 qt. 1 pt. Denominate Numbers. 181 Multiply : 1. 13 bu. 3 pk. 6 qt. by 2. 7. 25 lb. 4 oz. by 8. 2. 25 gal. 2 qt. 1 pt. by 3. 8. 33 min. 33 sec. by 9. 3. 7 lb. 10 oz. by 4. 9. 2 pk. 7 qt. by 10. 4. 23 bu. 3 qt. by 6. 10. 3 qt. 1 pt. by 11. 5. 32 gal. 1 pt. by 7. 11. 4 yr. 6 mo. by 12. 6. 3 hr. 15 min. 15 sec. 12. 5 wk. 6 da. 12 hr. by 5. by 16. COMPOUND DIVISION. 260. Divide 54 yd. 1 ft. 4 in. by. 20. 54 yd. -T- 20 gives a quotient of 2 yd., 2 — 2_j : IB; which is written, and a remainder oi 2 yd. 2 ft. 2 m. Ans. «. . _ . ' . . Aa ' , 14 yd. Reduce 14 yd. to 42 ft., and add 1 ft., making 43 ft. 43 ft. — 20 gives a quotient of 2 ft., which is written, and a remainder of 3 ft. Reduce 3 ft. to 36 in., and add 4 in., making 40 in. 40 in. -f- 20 gives a quotient of 2 in. which is written. Divide : 1. 13 wk. by 5. 7. 17 lb. 7 oz. by 3. 2. 15 lb. 9 oz. by 3. 8. 37 bu. 3 pk. 6 qt. by 2. 3. 2 lb. 3 oz. by 5. 9. 67 yd. 2 ft. by 4. 4. 2 gal. 1 qt. by 3. 10. 33 da. 15 hr. 57 min. by 3. 5. 5 bu. by 4. 11. 561 gal. by 6. 6. 7 hr. by 6. 12. 22 hr. 20 min. 20 sec. by 4. 13. 109 gal. 1 qt. 1 pt. by 7. 14. 273 yd. 1 ft. 6 in. by 9. 15. 155 bu. 3 pk. 2 qt. by 6. 16. 180 da. 19 hr. 28 min. by 8. i8* Chapter Four. 17. Divide 243 da. 4 hr. 2 min. by 15. Dividing 243 days 15)243 da. , 15 93 da. _90 da. 3 da. by 15 gives a quotient of 16 days and a re- mainder of 3 days. Re- ducing 3 days 4 hours to 76 hours and divid- ing by 15 gives a quo- tient of 5 hours and a remainder of 1 hour. Reducing 1 hour 2 minutes to 62 minutes and dividing by 15 gives a quotient of 4 minutes and a remainder of 2 minutes. Reducing 2 min- utes to 120 seconds and dividing by 15 gives a quotient of 8 seconds. 18. Divide 334 yd. 9 in. by 21. 15 yd. 2 ft. 9 in. 16 da. 5 hr. 4 min. 8 sec. 4 hr. 2 min. 4hr. 76 hr. 75 hr. lhr. 2 min. 62 min. 60 min. 2 min. 120 sec. 120 sec. 21)334 yd. ft. 21 124 yd. 105 yd. 19 yd. 9in. 57 ft. 42 ft. 15 ft. 9 in. 189 in. 189 in. 19. 825 lb. by 48. 20. 112 T. by 25. 21. 43 mi. by 32. 22. 84 yr. by 24. 23. 462 bu. by 32. 24. 1078 yd. by 62 i Insert the missing denomina- tion, feet, with a cipher prefixed. Reduce the 19 yards remainder to 57 feet. Reduce to 189 inches the 15 feet 9 inches remaining. 25. 288 hr. 9 min. by 54. 26. 863 gal. 2 qt. 1 pt. by 47. 27. 33 wk. 1 da. by 72. 28. 1138 T. 910 lb. by 81. 29. 1629 yd. 1 ft. by 96. 30. 1867 gal. 1£ pt. by 125. Denominate Numbers. 183 261. Avoirdupois Weight. Long Ton. In selling iron, coal at the mines, ores, etc., and in calculating the duties at the U. S. custom houses upon imported goods, the following table is used : 28 pounds (lb.) = 1 quarter (qr.) 4 quarters = 1 hundredweight (cwt.) 20 hundredweight = 1 ton (T.) 1 cwt. = 112 lb. 1 T. = 2240 lb. The ton of 2240 pounds is called a long ton. Unless otherwise specified in a problem, the cwt. of 100 pounds and the ton of 2000 pounds are to be taken. 262. Oral Problems. 1. How many tons and pounds of coal in 40 bags, each containing 80 pounds ? 2. If it takes 3 hr. 20 min. to hoe a row of corn, how long will it take to hoe 3 rows ? 3. A man puts up 3^- pounds of tea into 4 ounce pack- ages. How many packages does he make ? 4. 3 pk. 3 qt. of apples are divided among 9 children. What quantity does each child receive ? 5. What part of a day is 30 minutes ? 6. If there are 2\ gallons of wine in 12 bottles, how many pints are there in each bottle ? 7. What is the weight of two packages each containing 15 lb. 11 oz. ? 8. What part of an hour is 40 seconds ? 9. What is the rent of a house for 1 year 9 months at $16 per month? 10. If 3 gal. 2 qt. 1 pt. of milk are taken from a can con- taining 10 gallons, how much is left in the can ? 184 Chapter Four. 11. 5 hams weigh 61 J pounds. What is the average weight ? 12. There are on an average 41 pupils in a class. How many are there in 14 classes ? 13. At 37^- cents per yard, how many yards can be bought for $6.75? • 6f-*.$t = ¥ + t = ¥-*-t. etc. 14. Find the cost of 16 barrels of flour at $6.12£ each. 15. $1.65 is equally divided among 15 boys. What is the share of each ? 16. A floor containing 40 J square yards is 7 yards long. How many yards wide is it ? 17. How many ounces in 5J pounds ? 263. Written Problems. 1. If a watch gains 1 min. 17 sec. per day, how much will it gain during March and April ? 2. How many bushels, pecks, and quarts in 1449 pounds of corn, weighing 56 pounds to the bushel ? 3. Eeduce 25 T. 13 cwt. 2 qr. 25 lb. to pounds (long ton). 4. A chain, 97 yd. 8 in. long, contains 1000 links. Find the length of one of the links. 5. A farmer sold out of 5 bushels of peas the following quantities : 3 pk. 6 qt. ; 4 pk. ; 4 pk. 3 qt. ; 1 bu. 1 pk. 1 qt. How much has he still to sell ? 6. Change 100,000 pounds to tons (long), cwt., qr., lb. 7. A man walks on Monday 15 mi. 161 rd. ; Tuesday, 10 mi. 84 rd. ; Wednesday, 19 mi. 15 rd. ; Thursday and Friday, 12 mi. 121 rd. each day ; Saturday, 14 mi. 240 rd. What distance per day does he average ? Denominate Numbers. 185 8. If the sun rises at 5 hr. 10 min. a.m., and sets at 6 hr. 42 min. p.m., how long is the day ? How many hours and minutes of night ? 9. Find the duty at 1-j 2 ^ per pound on an invoice of tin weighing 33 T. 7 cwt. 20 lb. (long ton). 10. An iron rod is 12 ft. 6 in. long. Prom it are cut 73 bolts, each If inches long. How much is left ? 11. A man rows a mile in 10 min. 30 sec. How long would he take to row 27 miles at the same rate ? 12. What is the total weight in tons (long), etc., of 19 barrels of sodarash weighing 13 cwt. 2 qr. 10 lb. each ? 13. A man rows 51 miles in 23 hr. 5 min. and 30 sec. How long does he take to row a mile ? 14. If I lost $50 by selling a lot for two-thirds of its cost, what would I have lost if I had sold it for three-fourths of its cost ? 15. At the rate of $2.75 per day of 8 hours, how much should be given a man that works from a quarter before 8 in the morning until 5 minutes past 11 in the morning ? 16. If a railroad train travels 18 miles in 40 minutes, how far will it travel, at the same rate, in 1\ hours ? 17. A coal dealer buys 175 (long) tons of coal. How much does he receive for it at $ 5 per ton of 2000 pounds ? TIME BETWEEN DATES. 264. Oral Problems. 1. How many hours from 3 o'clock Saturday afternoon to 9 o'clock Sunday morning ? 2. How many days from May 1 to June 1 ? 3. A boy takes a spoonful of medicine every hour. If he takes the first dose at 2 o'clock, at what hour will he take the sixth ? The second ? The fourth ? 1 86 Chapter Four. 4. A man begins work on the morning of the 6th and ends on the evening of the 11th. How much does he earn at $ 3 per day ? 5. An importer receives some cases of goods numbered consecutively. How many cases are there if the lowest number is 29 and the highest number is 53 ? 6. How many posts 6 feet apart will be needed for a fence 120 feet long. For a fence 6 feet long ? 12 feet long? 7. Find the time from Jan. 1 to Jan. 31, counting the first and the last day. Omitting both days. 8. How many days from July 4 to Aug. 15, inclusive ? 9. How many chapters from the 25th to the 49th, exclusive ? 10. A girl begins at the 146th problem and solves all those on two pages. If the last is the 172d problem, how many does she solve ? 265. How many days from March 4 to Sept. 1 ? March 4 to March 31, 27 days Excluding March 4, there remain in the month 31 — 4, or 27 days. To this add the number of days in April, May, June, July, and August. Since March 4 is excluded, we take 1 day in September, making the total 181 days. In finding the time between dates, either the first or the last day is excluded; that is, from the 1st to the 21st is con- sidered 20 days. April 30 May 31 June 30 July 31 Aug. 31 Sept. 1 Ans. 181 days Denominate Numbers. 187 L How many days from 11. Jan. 1 to Feb. 19? 16. Feb. 29 to April 1 ? 12. Oct. 31 to Dec. 30 ? 17. May 21 to July 4 ? 13. Sept. 30 to Dec. 16 ? 18. April 7 to May 27 ? 14. Nov. 1 to Dec. 19 ? 19. June 10 to Aug. 1 ? 15. March 16 to April 25 ? 20. July 4 to Sept. 1 ? 267. Written Problems. Take note of leap year. How many days from : 1. Feb. 6, 1903, to Oct. 1, 1903 ? 2. Oct. 14, 1903, to March 3, 1904? 3. Jan. 1, 1904, to April 19, 1904? 4. Dec. 23, 1904, to March 8, 1905 ? 5. Sept. 3, 1903, to Feb. 1, 1904 ? 6. March 16, 1904, to Dec. 25, 1904 ? 7. June 3, 1905, to Nov. 29, 1905 ? 8. Aug. 17, 1903, to Jan. 3, 1904 ? 9. April 4, 1905, to July 4, 1905 ? 10. May 16, 1906, to Oct. 14, 1906 ? 11. How much wages at $4 per day should a man receive from Tuesday, Jan. 2, 1906, to Feb. 28, inclusive, no pay to be received for Sundays or legal holidays ? 12. A man borrowed $100 April 4, and returned it Nov. 25. How many days' interest did he owe ? (Do not include both days.) 13. May 1, 1903, fell on Friday. Upon what day of the week did July 4 fall ? 1 88 Chapter Four. 14. How many days does vacation last if it begins on the morning of Saturday, July 2, and school commences on the first Tuesday of September ? 15. A man borrows some money June 16, and agrees to return it in 60 days. On what date should he pay it ? 16. A traveller starts upon a trip Aug. 24, 1904, and reaches home again Feb. 10, 1905. How long is he away ? In each of the preceding examples the difference between the dates is less than a year, and the answer is required in days. When the difference is more than a year, it is generally obtained by compound subtraction, each month being considered as containing 30 days. 17. Find the difference in time between March 3, 1891, and Jan. 1,1905. ^ f % Writing 1905, 1st month, 1st day, we subtract 1891 3 3 1891, 3d month, 3d day. Ans. 13 yr. 9 mo. 28 da. 13 9 28 18. George Washington was born Feb. 22, 1732. How old was he at the signing of the Declaration of Indepen- dence, July 4, 1776 ? 19. Abraham Lincoln was -first inaugurated president March 4, 1861. How long had he served at his death, April 15, 1865? 20. The battle of Lexington took place April 19, 1775. The treaty of peace was signed Sept. 3, 1783. How many years, months, and days between the two events ? 21. How many years elapsed between the discovery of America by Columbus, Oct. 12, 1492, and the landing of the Pilgrims, Dec. 21, 1620? 22. General Harrison fought the battle of Tippecanoe Nov. 7, 1811. He was inaugurated president 29 yr. 3 mo. 27 da. later. Give the date of his inauguration. Percentage. 189 23. How long was it after the treaty with England, signed Dec. 24, 1814, that the Mexican treaty was con- cluded, Feb. 2, 1848? 24. General Taylor died July 9, 1850. How long did he live after the capture of Monterey, Sept. 24, 1846 ? 25. President Garfield was born Nov. 19, 1831. How old was he at his inauguration, March 4, 1881? 26. The last battle of the Mexican War took place Sept. 14, 1847. The battle of Bull Run was fought 13 yr. 10 mo. 7 da. later. What was the date of this battle ? 27. Find the time between July 4, 1776, and Jan. 1, 1904. PERCENTAGE 268 . Oral Exercises. 1. Find 4% of $125. 6. 33 J % of 1 day. 2. 25% of 16. 7. 62£% of $12. 3. 6% of 200 cows. 8. 9 % of $23. 4. 1% of 150 pounds. 9. 75 % of 3 gallons. 5. 20% of 65 yards. 10. lJ%of $400. 269 . Written Exercises. 1. Find 6% of $576. 9. 25 % of $156. $576 x .06 £ of $156 2. 41% of $340. 10. 1 % of $156. 3. 25 % of 1876 bushels. 11. i% of $156. 4. 121% of 864 cows. 12. 50 % of 480 hours, 5. 50 % of 432 yards. 13. \% of 480 hours. 6. 33^% of 576 soldiers. 14. 1% of $1420. 7. 16f % of 696 gallons. 15. 31% of $66. 8. 6J%of $4.96. 16. 7|% of 360 days. 190 Chapter Four. INTEREST. 270. Interest is the sum paid for the use of money. The Principal is the sum loaned. The Amount is the sum of the principal and interest. In computing interest, the year is considered as composed of 12 months of 30 days each. 271. Oral Exercises. Find the interest on : 1. $90 for 2 months at 4%. 2. $60 for 60 days at 6%. 3. $100 for 2 yr. 6 mo. at 5%. 4. $ 120 for 30 days at 5%. 5. $300 for 90 days at 3%. 6. $100 for 1 yr. 3 mo. at 4%. 7. $50 for 3 years at 6%. 8. $100 for 2 yr. 4 mo. at 6%. 272. Find the interest on $ 63 for 4 yr. 5 mo. at 5%. $63. .05 Find the interest for one year by multi- $ 3 15 plying the principal, $63, by the rate, 6, . 5 expressed as hundredths. Multiply this prod- t-r uct, $3.15, by the time expressed in years, '? 4&. * L31 + 12.60 Ans. $ 13.91 $ 63 is called the principal. 5 = rate. 4 yr. 5 mo. = time. Rate Interest = Principal x x Time (in years). 100 Interest. 191 The work may sometimes be shortened by indicating the operations and cancelling : 4 Find the interest on $160.50 for 3 mo. 15 da. at 6%. $ mn X j|j X ?- = $11 4 235 = $ 2.808 + Ans. $2.81. 4 Note. — The divisor, 100, should be cancelled only in performing the final division. Find the interest on $69.75 for 1 mo. 17 da. at 4%. $.007/75 s 47 • W-M X =gs X ^- = $ .36425. Ans. 36 cents. Note. — The three ciphers in the dividend are cancelled by moving the decimal point in the dividend three places to the left, prefixing a decimal cipher. 273. "Written Exercises. Find the interest on : 1. $192 for 3 yr. 7 mo. at 5%. 2. $ 60 for 2 mo. 12 da. at 4%. 3. $240 for 1 yr. 1 mo. at 6%. 4. $14.40 for 5yr. 5 mo. at 5%. 5. $36 for 77 days at 41%. 6. $99 for 21 months at 6%. 7. $ 192 for 2 yr. 4 mo. at 5%. 8. $600 from Jan. 1 to Jan. 16 at 4%. 9. $1200 from July 1, 1903, to Jan. 1, 1905, at 6%. 10. $57.60 from Oct. 4, 1904, to Feb. 4, 1908, at 5%. 192 Chapter Four. 274. Oral Problems. 1. 16 is how many hundredths of 64 ? 2. What per cent of 25 is 5 ? 3. What part of £ is f ? Change both to the same denominator : 16 twentieths, 15 twentieths. 4. What part of 2 lb. 1 oz. is 1 lb. ? Change both to the same denomination : 33 oz., 16 oz. 5. Divide 4 gallons by 3 pints. 6. How many pencils at 4 mills each can be bought for a dollar ? ! mill = ^ f a cent . 7. Write ^asa decimal. 8. Divide 34 by 200. 9. How many pounds in one-quarter of a ton? How many pints in .25 of a bushel ? 10. Change 37^, 75^, 8^, 62j£ 6{f, to fractions of a dollar ? 11. How many pounds of cheese at $0.16$ a pound can be bought for $5.00? 12. An agent collected rents amounting to $300. What was his commission at ^% ? 13. Find the interest of $200 for 1 yr. 3 mo. at 4%. 14. A farmer raised 50 bushels of cranberries, and sold 60% of them. How many bushels did he sell ? 15. What % of a number is fa of it ? 16. What would 42 pounds of butter cost at 33 \$ a pound? 17. When the tax rate is $12 per $1000, what will Mr. Smith's tax be if he owns $4500 worth of property ? Review. 193 18. A man pays $60 interest per year. How much, in- terest does he pay in 3 yr. 7 mo. ? 19. At $45 per month, what is the rent of a house for 2 yr. 7 mo. ? 20. Express in per cents : \ ; \\ \ ; \ ; -J-. 275. Written Problems. 1. What is the interest on $760 for 5 months at 3±% ? 2. A merchant insures property worth $20,000 for J of its value. How much does he pay, the rate for insuring being 1J%? 3. What is the commission on $56*^8 worth of cloth at 4. At 3%, what is the commission on the sale of 5000 pounds of sugar at 5^ per pound ? 5. What will be the interest on $720 for 3 mo. 24 da. at 6. A clerk's income is $800. He pays 25% of it for board, and 33 J % of the remainder for clothes. How much, has he left ? 7. \°lo of my money is in my pocket, 38% is in the bank, and the rest is in real estate. I have in all $ 24,000. How much is in the bank and in real estate ? 8. An auctioneer sold for Mrs. Paul, on 10 % commission, 14 chairs at $1.75, 6 tables at $2.75, 40 yards carpet at 62i^ a yard, and a miscellaneous lot for $119.24. What sum did Mrs. Paul receive after paying commission ? 9. How many feet in 62^% of a mile ? What part of a day is 18 hr. 30 min.? Reduce 9 cwt. 17 lb. to ounces. 10. If .625 of a cord of wood costs $3.75, what will .75 of a cord cost ? 194 Chapter Four. 11. A business man's receipts for a week are $2575. His average rate of profit is 5% of his receipts. What is his profit for the week ? 12. A certain city had 14,250 inhabitants in 1900. The population has increased 24 per cent. What is the present number of inhabitants ? 13. A class has 56 pupils on register. When 14^ per cent of the pupils are absent, how many are present ? 14. A merchant's sales for 1903 were $ 45,276. What should be the sales for 1904 to make an increase of 16f per cent ? 15. Thirty words were dictated as a spelling test. One pupil received a mark of 93J per cent. How many words did he misspell ? 16. A certain regiment went into battle with 1000 men. Of these 5% were killed, 12% were wounded, 3% were taken prisoners, and 1% were missing. How many re- mained available for duty? 17. What is the duty at 35 cents per square yard on a piece of cloth measuring 56 yards, 27 inches wide ? 18. A man bought a bill of goods amounting to $ 374.50, with a deduction of 2 % for payment within 10 days. How much does he save by paying the bill within the 10 days ? 19. A merchant places a bill of $ 840 in the hands of a collector, who collects 75% of the amount. How much does the merchant receive if the collector deducts 5% of the amount collected, as his commission ? 20. How many pounds of bread can be made from 5 bushels of wheat weighing 60 pounds per bushel, if the wheat loses 30 per cent in the process of grinding into flour, and if the bread weighs 33J per cent more than the weight of the flour used ? Measurements, *95 SURFACES. 276. Preliminary Exercises. 1. What is the length in inches of a row of four enve- lopes, each five inches long, placed end to end ? What is the length in feet and inches. 3 inches 1 p 2. What is the width in inches of four such rows, each envelope three inches wide, just touching each other ? What is the width in feet ? 3. How many envelopes are there ? How many square inches are there in each envelope ? How many square inches are covered by all of them? 4. How many envelopes 5 inches by 3 inches would cover the top of a table 4 ft. 2 in. long and 2 ft. 6 in. wide? 5. Draw a rectangle to represent a floor 24 feet long 18 feet wide. Draw rugs 6 feet long, 3 feet wide, and see how many will be needed to cover the floor. 6. What is the difference between three square inches and three inches square ? 7. What is the distance around a room that is 40 feet by 30 feet? 196 Chapter Four. 8. A garden is 12 feet long and 9 feet wide. How many bunches of flowers will it furnish, if it takes 3 square feet to furnish one bunch ? 9. A room is 36 feet long and 30 feet wide. How many- square yards in the floor ? 10. How many yards is it around a room 15 feet long and 12 feet wide ? 11. How many square inches in the surface of a sheet of paper 1 foot 8 inches long, 11 inches wide ? 12. How many pieces of paper 2 inches square will exactly cover a slate 12 inches long, 8 inches wide ? 277. Written Problems, 1. How many boards 12 feet long, 6 inches wide will be required for a floor 8 yards long, 6 yards wide ? The floor is 24 feet long, 18 feet wide ; its area in square feet is 18 x 24. The area of the board in square feet is 12 x J, or 6. Number of boards = 18 x 24 6 Note. — Labor is frequently saved in examples involving multipli- cation and division by first indicating the operations and then using cancellation. 2. How many bricks 8 inches by 4 inches will be needed for a walk 24 yards long, 6 feet wide, making no allowance for waste ? Area of top surface of one brick =(8x4) square inches. Tne length of the walk in inches = 24 x 3 x 12 ; width in inches = 6 x 12. Area of walk in square inches = 24 x 3 x 12 x 6 x 12. Divide this by 8 x 4, the number of square inches in the top surface of a brick. Number of bricks = 24x3x12x6x12 8x4 Note. — It will be remembered that the divisor and the dividend must be of the same denomination, square inches in this example. Measurements. 197 3. How many paving tiles \ foot square will cover a hearth. 6 feet long, 3 feet wide ? Make a diagram. 4. How many boards 12 feet long, 8 inches wide will be required for a close fence 120 yards long, 6 feet high ? 5. Find the number of paving stones 9 inches by 3 inches, in a street 100 rods long, 10 yards wide. 6. Draw a rectangle 2 inches by 3 inches. Draw one twice the size. What are the dimensions of the latter? What are the dimensions of one four times the size ? A plot 100 feet by 100 feet is how many times as large as a plot 25 feet by 25 ? 7. A brick is 8 inches long, 4 inches wide, 2 inches thick. How many square inches are there in the surface of the widest face ? In the surface of one side ? In the surface of one end ? 8. How many bricks laid on the widest face will be needed for a walk 28S inches long, 96 inches wide ? 9. How many bricks laid on the side will be needed for a walk 24 feet long, 8 feet wide ? 10. How many square feet are there in a roll of wall paper 24 feet long, 18 inches wide ? 11. How many rolls 24 feet long, 1\ feet wide, would be required to paper the ceiling of a room 45 feet long, 36 feet wide, making no allowance for matching or waste ? 12. The owner of a piece of ground 200 feet wide, 300 feet long, divides it into lots 25 feet by 100 feet. How many lots are there ? 198 Chapter Four. 13. Make table of square measure : square inches (sq. in. ) =1 square foot (sq. ft.) square feet = 1 square yard (sq. yd.) square yards = 1 square rod (sq. rd.) 160 square rods = 1 acre (A.) acres = 1 square mile (sq. mi.) 14. There are 160 square rods in an acre. How many square yards are there in an acre ? 15. Give the dimensions, in yards, of a field that will contain just an acre. Of one that will contain two acres. 16. At $80 per acre what is the value of a field 80 rods long, 70 rods wide ? What will it cost to fence the field at 20^ per running yard? 17. A man has a lot 100 feet by 200 feet. How many square feet will he have left for a garden after he builds a house 25 feet by 60 feet ? 18. One wall of a room is 24 feet long and 12 feet high. There is a door in it 8 feet high, 4$ feet wide. How many square yards of plastering will be needed to cover the wall ? 19. What would be the cost of painting 1800 feet of fence 6 feet high at 15 cents per square yard ? 20. What is the length of a rectangular field 60 rods wide that contains 60 acres ? 21. A farm is one mile square. How many 40-acre fields does it contain ? 22. How many acres in a field in the shape of a triangle whose base and perpendicular measure 40 rods each ? 23. How many acres are there in a triangular plot of ground when the base measures 80 yards and the perpen- dicular measures 60£ yards ? Measurements. 199 3 in. wide VOLUMES. 278. Preliminary Exercises. 1. How many one-inch cubes can be placed on the bottom of a box 4 inches long, 3 inches wide ? 2. If the box is one inch high, how many will it hold ? If the box is 2 inches high ? 3 inches high? Note. — A cube one inch long, one inch wide, one inch high, contains a cubic inch. 3. How many cubic inches in a box 3 inches long, 4 inches wide, 1 inch high ? In a box 3 inches long, 4 inches wide, 2 inches high ? 4 inches wide, 4 inches high ? In a box 4 inches long, 4. If you had 24 one-inch cubes, how could you pile them to make a solid with six rectangular faces ? 5. If the pile was 2 inches high, how many cubes would there be in each tier ? How many square inches would the lower tier cover ? 6. How could the 24 cubes be arranged to make a pile 3 inches high? 7. Can you give a rule for finding the number of cubic inches in a box 4 inches long, 2 inches high, 3 inches wide ? 8. How many cubic inches of water would a tin box hold, the dimensions of the box being 5 inches by 3^- inches by 4 inches ? 9. How many one-foot cubes could be placed in a cubical box one yard long, one yard wide, one yard high ? 200 Chapter Four. 279. A solid has three dimensions : length, breadth, and thickness. The volume or contents of a solid, is the space it occupies, expressed in cubic inches, cubic feet, cubic yards, etc. A cube is a solid hav- ing six equal square faces. 280. Cubic Measure. 1728 cubic inches (cu. in.) = 1 cubic foot (cu. ft.) 27 cubic feet = 1 cubic yard (cu. yd.) 281. Written Exercises. 1. How many cubic inches in a solid 3 yards long, 2 feet wide, 6 inches high ? How many cubic feet ? How many cubic yards ? To find the volume in cubic inches, change 3 yards to 108 inches, and 2 feet to 24 inches. Volume = (108 x 24 x 6) cubic inches. Volume (in cubic feet) = (9 x 2 x $) cubic feet. Volume (in cubic yards) = (3 x § X \) cubic yards. 2. How many cubic feet of air in a room 24 feet long, 18 feet wide, 12 feet high ? 3. Find the solid contents of a piece of timber 25 feet long, 3 feet wide, 5 feet thick. Is it larger or smaller than a piece 4 feet wide, 4 feet thick, and 23 ft. 6 in. long ? Measurements. aoi 4. How many cubic yards of earth will have to be re- moved in digging a cellar 18 feet wide, 55 feet long, 6 feet deep ? What will be the cost at 60^ a load (1 cubic yard) ? 5. A brick is 8 inches long, 4 inches wide, 2 inches thick. How many bricks are there in a pile 60 feet long, 20 feet wide, 5 feet high ? 6. Find the number of bricks in a wall 24 feet wide, 48 feet high, 1 foot thick, making no allowance for mortar, etc. 7. How many bricks are there to a cubic foot ? 8. Allowing 20 bricks to a cubic foot when laid in mortar, how many bricks will be needed for a wall 24 feet wide, 50 feet high, 20 inches thick ? 9. What will be the cost of building a stone wall 40 rods long, 4 feet high, 1 yard thick, at $ 6.40 per perch of 24| cubic feet ? 10. A cord of wood contains 128 cubic feet. If the wood is cut into 4-foot lengths, what should be the other two dimensions of a regular pile to hold just a cord? 11. How many cords of wood are there in a pile 24 feet long, 4 feet wide, 12 feet high ? 1 cord = 128 cubic feet. 282. Cubic Measure of Capacity. 231 cu. in. =1 gallon 2150.4 cu. in. = 1 bushel 128 cu. ft. = 1 cord 12. Find the capa- city in bushels of a bin 1 yd. long, 2 ft. 4 in. wide, 5 ft. 4 in. high. 202 Chapter Four. The capacity of a bin, 3 4 10 tank, etc., corresponds to fifi x gg x QAj __ the ooZume of the contents otg^ 3 Du * " dU Du * -***■ of the bin or tank when full. -t »go Write the dimensions in gaa inches as factors, with the $* number of cubic inches in a bushel as a divisor, and cancel. The decimal point in the divisor is moved one place to the right, and a cipher is added to one of the numbers above the line. 21504 is cancelled by 12, 7, 4, and 64. 13. Find the capacity in gallons of a tank 1 ft. 9 in. long, 1 ft. 3 in. wide, 1 ft. 10 in. deep. 21 x 15 x 22 -, rLL~i — gal. Cancel. 14. How many gallons are there in a cubic foot ? Give the answer as a mixed number ; as a mixed decimal. 15. How many cubic feet are there in a bushel ? Give the answer as a mixed number; as a mixed decimal. 16. Give the width of a wagon body 18 inches high, 6 feet long, that will hold, when full, a cubic yard. 17. A gallon contains 231 cu. in. Give the dimensions of a tin box that will hold exactly a gallon. 18. A pile of wood 40 feet long and 12 feet wide con- tains 1920 cubic feet. How high is it? 19. How much will it cost to have it cut if it costs 80 cents a cord ? 20. A pile of 4-foot wood is 16 feet long and 6 feet high. Required the cost at $ 5.50 per cord. 21. A rectangular tank is 5 feet long, 2 feet wide, and 2 feet deep. How many gallons of water will it hold ? Measurements. 203 22. What is the cost of digging a cellar 21 feet long, 18 feet wide, and 6 feet deep, at $ .28 a cubic yard ? 23. How much will a block of granite weigh 15 feet long, 12 feet wide, and 9 feet thick, if 9 cubic feet weigh 72 lb.? SURFACES OF RECTANGULAR SOLIDS. 283. Preliminary Exercises. 1. How many faces has a cube ? 2. What is the surface of each face of an inch cube ? 3. How many square inches are there in all the faces of an inch cube ? The accompanying diagram shows the dimensions of a piece of paper that will exactly cover a square prism, whose base measures 4 inches by 4 inches, and whose height is 8 inches. .9 .9* .9 4 in. J 00 4 in. 4 in. .9 00 4 in. 4 in. J 4 in. ■! .9 ooj °° 4 in. 1 4 in. .9 4 h 4. How many square inches are there in the top face of the prism ? In the bottom face ? In each of the four side faces ? In the four side faces ? In the two ends ? In the entire surface ? 204 Chapter Four. 284. Written Exercises. 1. Make a diagram of a piece of paper that when folded will just cover the six faces of a brick 8x4x2 inches. How many square inches of paper would be needed ? 2. The owner of a piece of ground 600 feet long, 150 feet wide, builds a fence 6 feet high around the plot. How many square feet of fence are there ? The surface of this fence may be considered as the four side faces of a solid. The area in square feet = (150 x 6) + (600 x 6) + (150 x 6) -f (600 x 6). The operation is shortened by adding 150, 600, 150, and 600, and multiplying the sum by 6. (1500 x 6) sq. ft. = 9000 sq. ft., Ans. 3. A room is 24 feet long, 18 feet wide, 12 feet high. Draw, touching each other, four rectangles representing the four walls. Write the dimensions of each wall. What are the dimensions of the large rectangle made up of the four smaller ones? Give the area in square feet. In square yards. 4. Show by a diagram the shape of a piece of paper that when folded will entirely cover a box 12 inches long, 6 inches wide, 4 inches high. Write the dimensions. This is called the " development " of the box. What is the area of the paper in square inches ? 5. How many square feet are there in a fence 10 feet high enclosing a lot 250 feet long, 200 feet wide ? 6. Make a diagram of a room 24 feet long, 18 feet wide, 12 feet high, showing the surface that is generally plastered. How many square yards of plaster will be needed for the above room, making no allowance for doors, windows, etc.? 7. A box is 4 inches long, 2 inches wide, and 2 inches deep. How many square inches on its surface ? With the pen, sketch a free-hand development of this box. Measurements. 205 8. One of the drawing models is a square prism 8 inches long and 4 inches square. How many square inches on the whole surface of the model ? 9. How many square yards in the walls of a room 12 feet wide, 15 feet long, and 9 feet high ? 10. The floor of a room is 18J feet long, 15^ feet wide. How many square yards in the ceiling ? A lot of land containing 5250 square feet is 125 feet long. How wide is it ? ANGLES, TRIANGLES, QUADRILATERALS. 285. The following may be drawn free-hand, the compasses being reserved for the geometrical problems in Chapter VIII. 1. Draw two lines meeting at a point. These lines make an angle. 2. Draw two lines that will make four angles. 3. Draw two lines so as to make two angles. Two such angles are called supplementary anglea 4. Make two equal supplementary angles. Equal supplementary angles are called right angles. A line making a right angle with another line is said to be perpendicular to it. 5. Draw two lines so as to make one right angle. Is the right angle made by two lines, each 10 feet long, any larger than a right angle made by two lines, each 1 inch long ? 6. What is the smallest number of straight lines that will enclose space ? Draw a figure enclosed by the smallest possible number of straight lines. What is its name ? Why ? 7. Make a triangle having one right angle. 206 Chapter Four. 8. Can you draw a triangle having two right angles ? Why ? What name is given to lines that will not meet, no matter how far they are extended ? 9. An angle less than a right angle is called an acute angle. Draw a triangle containing an acute angle. 10. Can you draw a triangle containing two acute angles ? Three acute angles ? 11. An angle greater than a right angle is called an obtuse angle. Draw a triangle containing an obtuse angle. 12. Can you draw a triangle containing three obtuse angles ? Containing two ? 13. Draw a triangle with sides 2 inches, 3 inches, 4 inches, respectively. A triangle having no two sides equal is called a scalene triangle. 14. Draw a triangle having two equal sides. This is called an isosceles triangle. The unequal side is called the 15. Draw an isosceles triangle with the base uppermost. With the base on the left. On the right. 16. Draw a triangle having three equal sides (an equilat- eral triangle). 17. Draw a square. Draw a rectangle 4 inches by 3 inches. How many right angles in each ? 18. Draw a four-sided figure having its opposite sides par- allel, but containing no right angle (rhomboid). What kinds of angles does it contain ? How many of each ? Write name in each angle. 19. Draw a four-sided figure, having all its sides equal, but containing no right angle (rhombus). Measurements, 207 20. Draw a quadrilateral (four-sided figure) having only two parallel sides (trapezoid). 21. Draw a quadrilateral having no parallel sides (trape- zium). 22. Draw a rhombus, each side 2 inches. A square, each side 2 inches. What is the difference between them ? Which is larger ? 23. A parallelogram is a quadrilateral that has its opposite sides parallel. Name the parallelograms that have four equal sides (equilateral) , Those that have four equal angles (equiangular). 24. The height of a parallelogram is called its altitude. Draw a rectangle, base 3^- inches, altitude 2-^- inches. Draw a rhomboid, base 3^- inches, altitude 2 J inches. Draw several rhomboids of the above dimensions, all differing in shape. 25. Cut out of paper a rectangle, base 3 inches, altitude 2 inches. Cut out a rhomboid, base 3 inches, altitude 2 inches. Place one upon the other, and see how their areas compare. 26. Can you calculate the number of square inches in a rhomboid whose base is 3 inches and altitude 2 inches ? 27. Draw a rectangle, base 4 inches, altitude 3 inches. Divide by a diagonal into two triangles. Mark in each triangle its area. 28. Draw a right-angled triangle, base 4 inches, perpen- dicular (altitude) 3 inches. Calculate its area. 29. Draw a rectangle, base 4 inches, altitude 3 inches. From the middle point of the upper base draw lines to the extremities of the lower base, making three triangles. Mark in each triangle its area. 30. Draw an isosceles triangle, base 4 inches, altitude 3 inches, and calculate its area. 208 Chapter Four. 286. Areas of Triangles and Quadrilaterals. Find the areas of the following : 1. A right-angled triangle whose sides meas- ure 15, 20, and 25 inches respectively. Note. — Area of triangle = £ product of base by altitude (perpen- dicular). 2. A right-angled triangle whose base measures 64 yards, perpendicular 48 yards. 3. A triangle whose base measures 18 rods, altitude 13 rods. 4. A square whose side measures 35 feet. Area of parallelogram = base x altitude. 97 ft. 5. A rectangle 42 yards by 37 yards. / j^ / Is 6. A rhombus whose base is 97 feet, Z I altitude 63 feet. Show that the area of this parallelogram is equal to that of a rectangle 97 feet by 63 feet. 7. A rhomboid, base 33 meters, altitude 28 meters. 8. A trapezoid whose paral- lel sides measure 10 and 16 feet, respectively, the perpendicular j distance between them being 6 feet. E 10 ft. 10 ft. U c Draw this trapezoid on a scale of \ inch to the foot, and measure AB, which divides the rectangle EFOH into two equal parts. AB = \(FG + ED). Cut off the triangle BCD and add it to the upper half of the trapezoid, so that CD will be a continuation of FO. The rec- tangle thus formed should measure 13 feet by 6 feet. Review. 209 9. A trapezoid as shown in the accompanying diagram. Draw to a scale ; cut off a triangle from A to the centre of CD, also one from B to the centre of EF\ and place these triangles above AB, so as to make a rectangle, £(10 + 16) feet long and 6 feet wide. 10. A trapezium, one of whose diagonals measures 42 yards, the perpendiculars to the opposite corners measuring 18 yards and 16 yards, respec- tively. Area in square yards = (42 x \ of 18) + (42 x \ of 16) = 42 x \ of (18 + 16). SPECIAL DRILLS.— REVIEW. 287. Oral Exercises. 1. 463 + 157 = 463 + 100 + 60 + 7 = In giving the solution at sight, the pupil says (or thinks) 663, 613, 620. 2. 256 + 184 4. 185 + 546 6. 167 + 734 3. 419 + 342 5. 668 + 193 7. 476 + 155 8. 4170 + 470 = 4170 + 400 + 70 Use no unnecessary words : 4570, 4640. 9. 1260 + 850 11. 3450 + 390 13. 5620+590 10. 2140 + 680 12. 4370 + 280 14. 6380 + 660 15. 400 — 163 = 400 - 100 - 60 - 3 = Say only 300, 240, 237. 2io Chapter Four. 16. 501-375 18. 650-488 20. 361-149 17. 275-137 19. 540-384 21. 455-358 22. 7310 — 6850 = 7310 - 6800 - 50 = 510, 460. 23. 8610-7680 25. 4960-4380 27. 6450-5760 24. 5000-4670 26. 2770-1890 28. 7320-6560 29. 24 X 66% = f of 24 hundred. 30. 48 x 16} 33. 24 x 62£ 36. 28 x 75 31. 32 x 37i- 34. 36 x 66| 37. 40 x 87£ 32. 49 x 25 35. 39 x 33^ 38. 88 x 12£ 39. 533£ -*- 66% = 5£ hundred -- f hundred = 16 -*- 2. 40. 337^-^-371 42. 687± -- 62| 44. 437£--87£ 41. 733J-r-33£ 43. 933|-f-66f 45. 212£-12| 288. Oral Problems. 1. How many ounces in 11^- pounds ? 2. 258 yards equal how many feet ? 3. A dealer bought 652 tons of coal and sold 476 tons. How much had he left ? 4. Sold my wheat for $ 347 and my oats for $ 154. How much did I receive for both ? 5. 40| yards of ribbon are cut into 7 pieces. Find the length of each piece. 6. How many square yards in a floor 5£ yards long and 6£ yards wide ? 7. What will be the cost of 14 pounds of lard at 14^ per pound? 8. At 1\$ each, how many lead pencils can I buy for 27^ ? Review. 211 9. What part of a 196-pound barrel of flour is contained in a 49-pound bag ? 10. At 45^ per yard, bow much lace can be bought for $1.35? 11. A woman has saved $ 833. How much more must she save to have $1000? 12. What will be the cost of 16 pounds of sugar at 4f^ per pound ? 13. Spent $ 2.56 for dry goods and $ 1.84 for groceries. How much did I spend for both ? 14. Find the cost of 3 lb. 10 oz. butter at 32^ per pound. 15. At $.375 per yard how much ribbon can be bought for $.75? 16. If it takes 1-J yards of cloth to make a jacket, how many can be made from a piece of cloth containing 30 yards ? 17. A boy paid 35^ for the use of a boat for 3J hours. What was the price per hour ? 18. If 13 pounds of raisins cost $1.69, what is the cost of 1 pound ? APPROXIMATIONS. 289. Give an estimate of the answer : 1. If 3 T. 1988 lb. coal cost $19.97, what will be the cost of 8 T. 1 lb.? Nearly 4 tons cost nearly $20. 2. At $ 500 per year, what will be the rent of a house for 1 yr. 11 mo. 29 da.? Nearly 2 years. 3. Find the cost of 5 barrels sugar, averaging 299 pounds each, at 4ff ^ per pound. 4. What is the interest on $199.86 at 6%, for 5 ma 28 da.? 212 Chapter Four. 5. If 11 men and 2 boys can finish a piece of work in 23£ days, how long will it take 23 men and 5 boys ? 6. What decimal of 639 acres is 321 acres ? 7. What will be the cost of 20,060 bricks at $ 4.90 per M ? 8. A farmer sells 5484 pounds rye at 87^ per bushel of 56 pounds. How much does he receive ? 9. If 19 lb. 15 oz. of tea cost $ 7.95, what will be the cost of 21 lb. 1 oz.? 10. Paid freight on 1987 pounds at 70^ per cwt. How much did I pay ? 11. If there are about 1\ gallons to a cubic foot, estimate the number of gallons in a tank 5 feet long, 3 feet wide, 4 feet high. 12. If there are about \\ cubic feet in a bushel, estimate the contents in bushels of a bin 5 ft. x 3 ft. x 4 ft. 13. Give the dimensions of a tank of 150 gallons' capacity. 14. Give the dimensions of a bin that will hold 100 bushels. 15. At 20 bricks laid in mortar to the cubic foot, give the length and the height of a wall 1 foot thick that can be built with a thousand bricks. 16. At $ 1 a load (1 cubic yard), give the dimensions of an excavation that can be made for $ 100. 17. A cubic foot of water (about 1\ gallons), weighs 62^- pounds. About what does a gallon weigh ? A pint ? 18. If iron is about 1\ times as heavy as water, about what does a cubic foot of iron weigh ? 19. About what is 49f% of f 801? 20. About what will be the interest at 6 per cent on % 100 for 3 yr. 11 mo. 29 da.? Review. 213 FUNDAMENTAL PROCESSES. 290. 1. The sum of two numbers is 278. One of the numbers is 89. What is the other ? 89 + ? = 278 2. The minuend is 583, the remainder is 249. What is the subtrahend ? 583 - ? = 249 3. The subtrahend is 56, the minuend is 214. Find the remainder. 4. The difference between two numbers is 84, the smaller is 129. What is the larger number ? 5. The subtrahend is 176, the remainder is 92. Find the minuend. 6. The multiplier is 98, the multiplicand is 809. Find the product. 7. The product is 9045, the multiplier is 45. What is the multiplicand? 8. The product of two factors is 1767. One of the factors is 93. Find the other factor. 9. The multiplicand is 84, the product is 2100. What is the multiplier ? 10. The dividend is 10,000, the divisor is 275. Find the remainder. 11. The quotient is 32, the remainder is 21, the divisor is 40. What is the dividend ? 40 ) ? 12. The dividend is 4263, the quotient is 203. Find the divisor. 4263 _ 2Q3 ? 13. The dividend is 267, the quotient is 13, the remainder is 7. What is the divisor ? 267 , o* H Chapter Four. RATIO. 291. Sight Exercises. - 87x25 * 75 63x19 3 * 21 5. gWil 7. 1x55 «, 74x24 2 * 37 A 96 x 27 4 ' 32 , gx42 8. ^x32 292. Written Exercises. Indicate operations, and cancel where possible. Terms compared *hould be of the same denomination. 1. If 90 tons of coal cost $472.50, what will be the cost of 132 tons ? $472.50x132 90 2. If 3 lb. 4 oz. tea cost $ 1.95, what will 12 oz. cost ? The ratio is 12 oz. to 52 oz. 3. A party of men can build 16 rd. 2 ft. of wall in 20 days. How long will it take them to build 4 yd. 6 in. ? Change to inches. 4. What will be the cost of 3 bu. 2 pk. 7 qt. of oats if 7 bu. 1 qt. cost $4.50? 5. By travelling at the rate of 20 miles a day, a person ■can complete a journey in 18 days. At what rate must he travel to finish it in 15 days ? 6. How many rolls of merino, each containing 75 yards, 'worth $ .45 per yard, will it take to pay for 180 yards of alpaca at $ .30 per yard ? 7. A merchant sold 20 hogsheads of oil, each containing ■63 gallons, at $ 1.75 per gallon, and invested the proceeds in table sauce in cases of 12 bottles each, worth $.31 J per bottle. How many cases did he buy ? Review. 215 8. No allowance being made for mortar, how many- bricks will be required to build a wall 50 feet long, 4 feet high, and 1 foot 3 inches thick, each brick being 8 inches long, 4 inches wide, and 2\ inches thicK '/ 9. If .1875 of a vessel cost % 273.12J, what is the value of -^ of it at the same rate ? 10. What is the cost of 60.51 tons of coal, when .9 of a ton costs §6.66? REVIEW OF FRACTIONS. 293. Add across : If the pupils work from their books the following examples in addition and subtraction, they should be permitted to write only the answers. The teacher should announce the number o* an example,, not taking them in order, then the number of the next «o be worked,, without giving time for the writing of unnecessary figures. 1. 13i-4-16| + 8f 6. 59f + 3£ + 4f 2. 4i + 5f + 27f 7. 7f-f-18f + 40i 3. 19i + 3f + 35£ 8. 35f + 5H + 8^ 4. 81 + 9^ + 14! 9. 3J + 9J + 25^ 5. 23f + 5J + 32^ 10. 66J + 8f + 14i 294. Subtract across : 11. 25\ -18^ 16. 68| -6{i 12. 63| -49f 17. 100£ - 62J 13. 70^-15£ 18. 56{ -37£ 14. 92f -24J 19. 83|. _43| 15. 33J -15^ 20. 42J -16} 2i 6 Chapter Four. Multiply : When the fractions are small and the fraction in the multiplicand has 1 for its numerator, business men do not change the mixed num- bers to improper fractions. In multiplying 38f by 11, the product of f by 11 is mentally reduced to 8£, and \ written ; 11 eights (88), and 8 (96), 6 being written ; etc. \ of 38| is 4 (written) with 6f remainder. This is reduced to ^ men- tally, and its }, or ||, written.* 37} x 3} 12f X 5} 38 fxlli 1121- 18| 63f 426} 131} Ans. 68 Ans. 431 h Ans - 21. 48} x 4} 24. 18} x 5} 27. 45} x 2i 22. 64} . : 10} 25. 13} x 7} 28. 50} x 10} 23. 29f x 6} 26. 9fx8} 296 1. Divide: 29. 13)2051 The pupil should endeavor to work the following by short division : into 20, once ; into 75, 5 times, remainder 10$ or -^ • ^ of -^ = f£. Ans. 16ft. 30. 14)186} 37. 21)450} 44. 25)568} 31. 15)250} 38. 31)970} 45. 32)965} 32. 16)198} 39. 24)553$ 46. 36)722£ 33. 17)190£ 40. 23)466f 47. 16)366} 34. 18)200} 41. 26)290£ 48. 17)208} 35. 19)381} 42. 27)545 J 49. 21)640} 36. 22)264} 43. 33)9994 50. 22)888} Review. 217 REVIEW OF DECIMALS. 297. Sight Exercises. Give products : 1. 360 x. 25 8. 840 x .075 15. 400 x .04 2. 560 x. 125 9. 960 x .005 16. 165 x .06| 3. 240 x. 375 10. 1200 x .001 17. 176 x .06^ 4. 400 x .625 11. 1500 x .002 18. 3300 x .00£ 5. 480 x. 75 12. 96 x .3£ 19. 880 x .12£ 6. 320 x. 875 13. 840 x .02£ 20. 105 x .8 7. 720 x. 025 14. 1500 x .06 21. 210 x .10 298. Give quotients : 1. 240 -h.5 8. 37 -*- .05 15. 76 -*- .04 2. 360 -i- .75 9. 48 -T- .005 16. 88 -*- .00£ 3. 45 -.125 10. 72 - .025 17. 65 -*• .12^ 4. 23 -h.25 11. 92 - .002 18. 84-^.8 5. 360 -.375 12. 93 - .03J 19. 11 + .06J 6. 100 -.625 13. 54 -v- .02£ 20. 42 -.6£ 7. 154 -.875 14. 132 -r- .06 21. 93-^.5 299. Written Exercises. 1. Find the value of (6.125 + 8.75 - 9.1235) -r- .0125. 2. Find the value of (1708.4592 - .00024) x .003. 4. Multiply 24.234 by .346, and write the result in words. 5. Divide 96 ten-thousandths by 384 hundred-millionths. ai8 Chapter Four. 6. Why does the value of a decimal remain unchanged when ciphers are annexed ? 7. Write : four hundred seven thousandths. 8. Write : six hundred four millionths. 9. Write in words 405.0067542. 10. Reduce to common fractions in lowest terms: .004; .0125; 56.37$. 11. 16f x .045 = ? .324 x .33J = ? 3.406 x 1.00 = ? 12. .805 -^ .35 = ? 80.5 -f- 350 = ? Divide twenty-five thousandths by 16 millionths. 13. Write in words : .0105; 000125; 1.001105; 11.4141; .000008. 14. Reduce to common fractions : .95 ; .526. 15. From one thousand and (decimal) five thousandths take eight hundred and (decimal) eight hundredths. 16. Divide eight hundredths by four thousandths, and multiply the quotient by six ten-thousandths. 17. Find the product of the following factors: .064, ,0032, 15,625, and 31.25. 300. Oral Eeview Problems. 1. At 20^ per quart, what will be the cost of 2 gal. 3 qt. 1 pt. of maple syrup ? 2. Find the cost of 4 T. 400 lb. of coal at $ 5 per ton. 3. A man puts 4 lb. 8 oz. of tea into 9-ounce packages. How many packages does he make ? 4. 4 pk. 3 qt. of apples are given to some children. If each child's share is 5 quarts, how many children are there ? 5. If it takes 3 hr. 20 min. to hoe a row of corn, how many rows can a man do in 2 days of 10 hours each ? Review. 219 6. How many dozen eggs at 25^ a dozen must be given for 100 pounds of sugar at 5fi a pound ? 7. Which would you rather have, -J of a dollar or 75^ ? Why? 8. What will a gallon of molasses cost if a gill costs 2\f ? 1 gill = £ pint 9. Give the names to the results in the four simplest processes in arithmetic. 10. $15 per week is how much per day ? 11. I of 72 is f of what number? 12. How many cubic feet in -| of a cubic yard ? 13. Which is the larger and how much larger, | of 130 or f of 119? 14. Which is the larger and how much, ^ or f ? 15. How many cubic feet in a wall 30 feet long, 4 feet high, and 2 feet thick ? .16. Iff of a barrel of flour cost $2.13, what cost 1^ barrels ? • 17. The difference between 144 and 24 is how many times 15 ? • 18. John walked 12f miles, and Henry lOf miles. How much farther did John walk than Henry ? 19. At 41^ a pint, what will 5 qt. 1 pt. of milk cost ? 20. After spending f of his money, James has $ 150 left. What amount did he have at first ? 21. How many gallons in 462 cubic inches ? 22. If a boy eats f of a loaf of bread, how many boys will be required to eat 10 loaves ? 23. 5 yd. cloth cost 90^ ; find the cost of f yd. 24. If | yd. of cloth costs 10^, how many yards can. b© bought for 80^ ? 220 Chapter Four. 25. A step is 3 feet. 2 steps are what part of a rod ? 26. 19+3 + 17 + 6 + 15 + 4=? 27. John had 85^. He bought strawberries for 22^-; 1 pound coffee for 30^ ; 3 sheets paper at 1^ a sheet. What remained ? 28. Three-fourths of a mince pie is worth 18^, and James eats ^ of a pie. What is the value of what he eats ? 29. If I have 1 pk. 2 qt. 1 pt. of meal, how many more quarts must there be to make 1 bushel ? 30. Charles caught 12 fish, worth 41 ^ each, in four hours. His time was worth 12^ an hour. Gain or loss, and how much ? 31. How many times would a dish holding f of a pint have to be filled to measure 9 quarts ? 32. If 5 chairs cost $ 80, what will 12 chairs cost ? 33. How many hours from 4 a.m. to 8 p.m. ? 34. Eeduce ff to lowest terms. 35. Add -J- to |, and take the sum from 5. 301. "Written Eeview Problems. 1. What part of 6 hr. 54 min. are 3 hr. 15 min. ? 2. If a man walks at the rate of 3 mi. 96 rd. per hour, how far will he walk in 3 hr. 20 min. ? 3. What is one-ninth of 28 bu. 3 pk. 7 qt. ? 4. Three men buy a house for $ 1200. A furnishes $600; B, $400; C, $200. They sell the house for $1500. How much money should each receive ? 5. If 5 T. 1000 lb. of coal cost $30.25, how much will be paid for 7 T. 320 lb. ? 6. At 25^ per hour, how much should a man receive that works 8 hours and 36 minutes ? Review. 221 7. If 2 lb. 4 oz. of tea cost $1.35, what will be the cost of 11 lb. 12 oz. ? 8. How many square inches in a paving tile 6 inches square ? How many square inches in a rectangle 4 feet by 3 feet ? How many paving tiles 6 inches by 6 inches would cover a surface 4 feet by 3 feet ? 9. A man buys a house and lot for $3000. He pays -f of the amount in cash and the remainder after 1 year, 4 months, with 5% interest. Find the amount of the second payment. 10. Find four-ninths of 28 bu. 3 pk. 7 qt. 11. (fof D + (fof 0-Cftcf 2) = ? 10 tiia A Qf4 f __* I of 15 1J x 11 ' 13. AU.8f+f+f+.A,tt 14. Find the value of 728 - 1 - \ - £ - \. 15. 1}.X <&.-**) X& 16. Eeduce ^ of f of £ of ^^ to a decimal. 17. A person owning ^ of a factory sells 75 per cent of his share for $ 1710. What is the value of the whole fac- tory? 18. Find f of 2 da. 5 hr. 40 min. 19. If a piece of cloth is 20 yards long and f yard broad, how broad is another piece which is 12 yards long and con- tains as many square yards as the first ? so. Simplify |l±l| x ^. * 21. If 7 men can do a piece of work in 10 J days, how long will it take 8 men and 5 boys to do the same work, each boy doing one-half as much as a man ? 222 Chapter Four. 22. A farmer drew to market three loads of wheat, weighing respectively 2873 pounds, 3027 pounds, and 2911 pounds. At 93^ per bushel (60 pounds), how much did he receive for the three loads ? 23. How many acres of land are there in a rectangular farm J of a mile long and f of a mile wide? (1 square mile = 640 acres.) 24. Eeduce ^""^ * to a simple fraction. 25. The sum of two numbers is 15f, and one of them is 9^5". Find the other number. 26. If 3 be added to both terms of the fraction -f, will the value be increased or diminished, and how much? 27. Make and solve a problem to illustrate reduction descending; one to illustrate reduction ascending. 28. How is the value of a fraction changed by increasing its denominator? Why? 29. Add % hours, 20| minutes, and 49.2 seconds. Ex- press the answer in minutes and seconds. 30. What fractional part of 31^ is 12|? 31. In a hotel the weekly wages of the clerk are $ 15, of the cook $ 7.50, of the porter $ 9, of the waiter $ 3, of the hostler $6, and of the errand boy $4. Find the average wages paid. 32. A man was born May 24, 1832. What is his age to-day? 33. A grocer's bill for $ 84.36 is paid 8 months 15 days after it becomes due, with interest at 5%. How much is 34. Find the cost of 7 lb. 11 oz. of cheese at 13^ per pound. Review. 223 35. Find the cost of digging a cellar 30 feet long, 15 feet wide, and 5 feet deep, at 30^ per cubic yard. 36. John Smith bought of Clark and Jones, 4 lb. 13 oz. beefsteak @ 21^ per lb. 12 lb. of bacon @ 12j£ Make a properly receipted bill of the above, dated at the time and place of this lesson. 37. Find the cost o 2315 pounds of coal at $ 5.75 per ton. 38. Write 1249 in 1 oman notation. 39. Given the dividand 807 and the quotient 34 J, find the divisor. 40. What will it cost to fill a jug, which contains 2310 cubic inches, with vinegar at 7 cents a quart ? (1 gal = 231 cu. in.) 41. Mrs. C. B. Jones bought of Cole, Steele, & Co., of Indianapolis, as follows: Nov. 12, 1904, 23 yards of muslin @ 16|^; 45 yards of sheeting @ 12^ ; Dec. 7, 12 yards of silk @ $1,621^; 8 handkerchiefs @ 45^; 2 pairs kid gloves @ $ 1.371 ; 6 neckties @ 75^. Make out and receipt the above bill. 42. If a boy bought f of a bushel of nuts for $2.00, and sold them for 12^ a quart, what was his gain ? 43. Reduce -^ of an inch to the fraction of a rod. 44. Eeduce 35 quarts to the fraction of a barrel (31 J gal.). 3450 cubic feet to cubic yards. 45. Put the following in the proper form of a bill, find the amount of the bill, and receipt it : David Wilson bought of Harry Lloyd, June 10, 1904, 7 pounds of oatmeal at 6^ a pound ; 10 pounds of sugar at 7$j a pound ; 14 pounds of ham at 13£^ a pound ; 3 brooms at $ 2.25 a dozen. 224 Chapter Four. 46. A family uses 2 quarts of milk a day. At 24/ a gallon, what does the milk cost for May and June ? 47. From March 3d to Sept. 19th is how many days? Do you include one of the days mentioned, or both of them, or neither of them ? 48. How many minutes from 8.10 a.m. to 9.25 p.m. 49. Subtract 40 rd. 3 yd. 2 ft. from 81 rd. 1 yd., and multiply the remainder by 10. Work by compound sub- traction and multiplication, and get an answer that contains no fraction. 50. Draw and divide a figure so as to show how many square feet in a rectangle that is 5 feet long and 3 feet wide. Draw and divide a figure so as to show how many square inches in a surface that is 4 inches square. These drawings are to be free-hand, and made with your pen. 51. Keduce 7 months and 15 days to the decimal of a year (360 days). 52. Eeduce .32175 of 1 ton to whole numbers of lower denominations. 53. If the perimeter of a square is 10 rods, what is the area? Find the area of a field, whose parallel sides measure 20 and 30 rods, respectively, the perpendicular distance between them being 15 rods. 54. Bought 5 bushels of berries for $ 5 and sold them at «8> .20 a quart. How much did I gain ? 65. From a tract of land 15 rods square I sold 65 square rods. What was the value of the remainder at $ 20 an acre ? 66. What is the cost of fencing a lot 9 rods square at $ .12 a foot? Review. 225 57. How many square yards are there in the walls of a rocm 20 feet long, 18 feet wide, and 9 feet high ? 5S. What must I pay for the laying of a sidewalk 6 rods long and 5 feet wide at $ .45 a square yard ? 59. How much will it cost to plaster a room 18 feet long, 15 feet wide, and 9 feet high, at $ .17 a square yard, deduct- ing 108 square feet for doors and windows ? 60. Mr. Thompson has a field, around which he wishes to build a tight board fence. The field is 50 rods long and 45 rods wide. The fence is to be 4J feet high. At 3JP a square foot, what will be the cost of the fence ? 61. . A man having $ 100 went to market. He sold 10 bushels of potatoes at 80^ per bushel, 2 tons of hay at $ 15 per ton, and 25 bushels of oats at 45^ per bushel. He bought 15 barrels of flour at $ 4.50 per barrel, and 12 yards of broadcloth at $ 4.75 per yard. How much money did he have left? 62. Cost of a pile of wood 10 feet long, 4 feet wide, and ^ feet high, at $ 7.50 a cord ? I wish to pile 60 cords of wood in such a manner that it will be 4 feet wide and 6 feet high. How long must it be ? 63. Find the interest of 1 263.75 for 1 year, 3 months, 20 days, at 6%. 64. At $ 17.625 a ton, how many tons of hay can be pur- chased for $ 95 ? 65. Mr. Ames owns \\ of an acre of land. Mr. Jones owns -| as much, which is \ of what Mr. Brown owns. What part of an acre does Mr. Brown own? 66. Four men built a barn. A worked 2 days ; B, 6 days \ C, 8 days; and D, 12 days. They received $84 What was each man's share? 226 Chapter Four. 67. A man has 768 hens, which is \ more than he had last year. How many had he then ? 68. Two trains are 87£ miles apart and running toward each other, one at the rate of 50f miles an hour, and the other at the rate of 20f miles an hour. How far apart will they be in half an hour ? 69. If 35 men earn $ 87.50 in 1 day, how much will 50 men earn in 10 days ? 70. Multiply 9008 by 7080, and divide the product by 600. 71. What is the difference between 69 x 58.8 and 291 -*- 0.97? 72. Find 6\% of 19,712 miles. 62i% of 2768 yards. 9^% of 11,223,344 pounds. 73. What is the interest of $ 150 for 2 yr. 8 mo. 15 da., at 6% per annum. 74. Add : 25,037.45 ; 8,712.23 ; 9050.37 ; 815.25; 91,017.16 ; 419.19; 2035.75; 15,025.55; 7079.13; 14026.27. 75. Add : 87.27 ; 43.75 ; 72.50 ; 39.75 ; 64.04; 58.94; 95.83 ; 26.37; 75.96; 50.83; 39.49; 97.08; 62.62. 76. A lot of land containing 5250 square feet is 125 feet long. What is the perimeter ? 77. A man spent ^ of his money for a house, -^ for furniture, -g^j- for horses, and ■§• to build a church. What part of his money had he left ? 78. Bought 10,752 cubic feet of wood at $8J a cord. What did it all cost? 70. Change * ? to a simple fraction. 80. 9| times £ of 56| is how much ? Review. 227 81. What is the cost of digging a cellar 27 feet square and 9 feet deep at 25^ a cubic yard. 82. How many yards of fence will be needed to enclose the plot of ground shown in the following diagram ? 5 rods 4 rods to 3 1 H 19 rods TO 83. The above field was originally a rectangle, but the owner sold one piece 5 rods by 3 rods, and a second piece 3 rods by 7 rods. How many square rods did it contain at first ? What is its present area ? 84. Calculate the number of square yards in the field shown in the accompanying diagram. 24 yds.. € 24 yds. 85. A man buys a piece of ground 300 feet long, 150 feet wide. He builds a house, 50 feet by 30 feet, and a shed 12 feet by 13 feet. How many square feet will he have left for a garden ? 228 Chapter Four. 86. The owner of a piece of ground 250 feet long, 200 feet wide, takes 10 feet from each side to make a gravel walk, and uses the remainder for a garden. Give the dimensions of the garden and its area in square feet? How many- square feet in the whole piece of ground? How many square feet are taken up by the walk ? 87. How many square feet of flagging would be required for a sidewalk 10 feet wide outside a lot 250 feet long, 200 feet wide ? 88. If a piece of carpet is 27 inches wide, and contains 48 square yards, how long is it ? 89. I have bought 24 yards of dress goods, 27 inches wide. How many square yards does the piece contain ? How many yards of lining 32 inches wide will contain the same number of square yards ? 24 yards long. ? yards long. I yd. 18 sq. yd. 18 sq. yd. I yd. CHAPTER V. PAGES Percentage 229 to 276 Finding Percentage, Base, Rate ; Commission, Insur- ance, Duties, Taxes, Profit and Loss, Commercial Discount, Interest, Partial Payments, Bank Discount, Interest by Aliquot Parts. Denominate Numbers 277 to 291 Reduction Descending and Ascending, Addition, Sub- traction, Multiplication, Division, Review. Review of Simple Numbers 291 to 309 PERCENTAGE. 302. Preliminary Exercises. Per cent means hundredths. Seven per cent means seven hundredths, y^j-, or .07. It is written 7%. How many hundredths of a number is one half of it? J = how many hundredths ? \? $7 f? -f? What per cent of a number is the half of it? J? J? £ ? i? i? A? A? A? A? t**? A*? What per cent of a number is f of it? J? £? f ? A? A? A? A? A*? 303. 1 per cent of a number is equal to what fraction of it? 3%? 5%? 9%? 10%? 15%? 20%? 25%? 30%? 40%? 50%? 60%? 75%? 90%? 304. What fractions are equal to the following ? 12$%? 16|%? 33|%? 37$%? 6J%? 62$%? 66$%? 87J% ? $% ? i% ? 2$% ? $% ? 305. 3 times a number is what per cent of it ? 2 J times ? li times ? 4$ times ? 229 230 Chapter Five. 306. Oral Exercises. 1. Find 37J% of $24. 37J % of $ 24 = f of $ 24, or $ 9. Ans. $ 9. 2. 6% of 150 bushels. 1% of 150 bushels = 1.6 bushels = \\ bushels; and 6% is 6 times 1£ bushels, or 9 bushels. Ans. 9 bushels. 3. 81% of 300 horses. 81 % of 100 horses = 81 horses ; of 300 horses it is 3 times 81 horses, or 243 horses. Ans. 243 horses. In examples 2 and 3 the pupil should be led to see that he can point off two decimal places in the multiplicand instead of in the multiplier ; without changing the result. The above analyses are suggestive merely. The form given in the third example is to furnish an explanation for the use of 3 as a multiplier. 4. Find 37|% of 1 gallon. 37 1 % of 1 gal. = f gal. = 3 pt. = 1 qt. 1 pt., Ans. 5. Find 121% of 1 gallon 15. 66f% of 66 horses 6. 371% of $24 16. l'6f%oflyard 7. 33 J % of 81 cows 17. 81% of $300 8. 6% of 150 pounds 18. 2^% of 80 sheep 9. 4% of 125 bushels 19. 40% of $2.50 10. 62£% of 1 peck 20. 20% of 65 rods 11. 4}% of $200 21. 10% of 15 pounds 12. 99% of 200 gallons 22. 3J% of $60 13. \% of $640 23. £%of$72 14. \% of 800 yards 24. lJ%of$96 The skilful teacher will appreciate the importance of rapid work, and will gradually shorten the time to be given to a class for the solu- tion of an oral example. She will also vary her methods of conducting the recitation, so as to keep up the interest of the pupils. Percentage. 231 TO FIND THE PERCENTAGE. 307. "Written Exercises. 1. Find 6% of $91.50. Multiply the base, $91.50, by the rate, 6, ex pressed as hundredths. The result, •$ 5.49, is called the percentage. $91.50 x.06 $5.4900 Arts. To find the percentage, multiply the base by the rate expressed as hundredths. 2. 331% of $28.80. While the rule is the same, to multiply $ 28.80 by .38^, the pupil should not fail to change 33£ hundredths to one-third. 3. \% of $1240. i°/o = jhj' Divide by 800 by cancelling the two ciphers in the divisor and making two deci- mal places in the dividend. 3 )$ 28.80 $9.60 Ans. 12.40/ $1.55 Ans. 4. 41% of $92.40. $92.40 x .04£. 5. 450% of $92.40. $92.40 x 4.5. 6. 12% of $37.50 14. 860% of $38 7. 20% of $51.60 15. \% of $2496 8. 1400% of $89.70 16. 25% of $52.36 9. 12i% of $73.28 17. 60% of $33.30 10. 131% of $27.60 18. 8% of $19.50 11. 6|% of $25.60 19. 6|% of $47.40 12. 3£% of $47.40 20. 12% of $62.50 13. 5£% of $29.50 21. 4i% of $ 71.50 232 Chapter Five. 22. 40% of $28.30 26. 75% of $59.20 23. 160% of $39.40 27. 87|%of$392 24. 84% of $23.75 28. 93f % of $496 25. 66f% of $825 29. |f% f$496 Suggestion. — The teacher»should have a preliminary sight lesson on these examples before giving them out for written solution. TO FIND THE BASE OR THE RATE. 308. Preliminary Exercises. 1. 40 is one-half of what number ? 2. 40 is .5 of what number? 3. 40 is 50% of what number ? 4. 40 is what part of 80 ? 5. 40 is what decimal of 80 ? 6. 40 is how many hundredths of 80 ? 7. 40 is what per cent of 80 ? 8. 26 is what per cent of 65 ? 26 is ff of 65. The fraction § £ equals £, or 40 hundredths. Ans. 40 per cent. 9. 26 is 40 per cent of what number ? If 40 hundredths of a number is 26, the number equals 26 divided by 40 hundredths, or 26 -f- .40. Ans. 65. To find the base, divide the percentage by the rate expressed as hundredths. To find the rate, divide the percentage by the base, expressing the result in hundredths. Another method of finding the base or the rate is suggested in the illustrative examples on the next page, which give young pupils an introduction to the equation, a powerful instrument in mathematical investigation. Percentage. 233 . Written Exercises. 1. What per cent of 65 is 26 ? This means, how many hundredths of 65 will equal 26 ? which may be expressed in the following form : 65 x — = 26. 100 The rate being required, the foregoing may be written as follows : 65x — = 26, or ^ = 26. 100 100 This is called an equation. To solve the equation, that is, to obtain the value of r, the general method is to clear the equation of the frac- tion by multiplying both sides by the denominator of the fraction, 100. This gives 65 r = 2600, or 65 times r equals 2600. r, therefore, is equal to 2600 divided by 65. Ans. 40 per cent. Proof. — 65 x 40 hundredths = 26. 2. 40 per cent of what number equals 26 ? & X i°- = 26, or ^ = 26. 100 ' 100 Clearing of fractions, 40 b = 2600 ; b = 65, Ans. Proof. — 40 % of 65 = 65 x .40 = 26. 3. 75 per cent of a number is 42. What is the number ? 78% = I bx— = 42, or ^=42. 100 4 Clearing of fractions, 3 6 = 168 ; b = 56, Ans. 4. What number is 15 per cent of 84 ? p = 15 hundredths of 84. 5. 24 is 18 per cent of what number ? 6. 27 per cent of a number is 81. What is the number ? 234 Chapter Five. 7. A boy spelled correctly 20 words of 25 given out What per cent of the- words did he spell correctly ? Note. — 25 is the base, 20 is the percentage ; required the rate. 8. 132 is 120 per cent of what number ? 9. -J- per cent of a number is 23. What is the number ? 10. f = what per cent of -f ? i x _?! = §. Cancelling, -!-=-?. 5 100 5 b 125 5 Clear of fractions by multiplying both terms of the equation by 125. Prove the correctness of your answer. 310. To clear an equation of fractions, multiply both terms of the equation by the least common denominator of the fractions. 11. i is what per cent of f ? 12. f is what per cent of £ ? 5 100 4 ' ' ' 125 4 13. 3J is what per cent of § ? 14. What per cent of $ 389.50 is $ 124.64 ? 15. $ 174.04 is 95% of what sum of money ? 16. f% of a number is 81. What is the number ? ifa of 6 = 81. 17. 984 is 133£% of what number ? 18. What number increased by 33£% of itself equals 984? Let n represent the number. Then n + - = 984 ; i. e. — = 084. Clearing of fractions, 4 n = 984 x 3 = 2952. n = 738, Am. Proof. — 738 + 33$ % of 738 = 738 + 246 = 984. 19. What number increased by 25% of itself equals 85? Percentage. 23 5 311. Oral Exercises. 1. 3 is what part of 6 ? 2. 3 is what decimal of 6 ? 3. 3 is how many hundredths of 6 ? 4. 3 is what per cent of 6 ? 5. 6 is what per cent of 3 ? 6. What number is 50% of 6? 7. 3 is 50% of what number? 8. 2 is what % of 100 ? 9. 2 is what % of 200 ? 10. What number is 5% of 100 ? 11. What % of 20 is 1? 12. 4 is what % of 200? 13. 3 is \°lo of what number ? 14. What per cent of 9 is 20J ? ~ = 20^ ; 9 b = 20£ hundred ; b = 2\ hundred = 225, Ans. J.0U 15. What number, increased by ^ of itself, equals 10 ? 16. What number, increased by 25 % of itself, equals 20 ? 17. 65 diminished by 5% of itself equals what ? 18. Buying price $ 100, selling price $ 112.50. Gain % ? 19. Cost $ 80, profit 20%. Selling price ? 20. What principal will give $ 30 yearly interest at 6% ? 21. A man had $ 600 in the bank. He drew out 16f per cent of it. How many dollars remained in the bank ? 22. A lost 40 per cent of his money, and had $ 750 left. How much had he at first ? 236 Chapter Five. 23. If I am compelled to lose 12^% on damaged goods, how must I sell those that cost me $ 5.60 ? 24. A man put $15, which was 16|% of his month's salary, in the bank. What was his month's salary ? 25. If each boy eats 60% of a loaf of bread, how many boys will eat 6 loaves ? Note. — In the solution of the foregoing oral problems, pupils should not be compelled to use the method suggested for the written exercises. REVIEW. 312. Written Problems. 1. A man receives from a bank 4% a year as interest on money he has in the bank. If his interest for a year is $ 60, how much money has he in the bank ? 2. A city had a population of 4500 at the end of 1903. The population at the end of 1904 was 1080 greater. What per cent did the population increase during the year ? 1080 = what per cent of 4500 ? 3. A person who sold an article for 25% more than its cost, received $ 85 for it. What was the cost ? Cost + £ cost = $ 85. 4. A person receives $ 45 annual interest on $ 1000. What rate per cent does he receive ? 5. A farmer sold 16J per cent of his sheep, and had 75 remaining. How many had he at first ? 6. A clerk has an income of $1100 per annum. He pays 20 per cent of it for board, 1£ per cent for washing, 2 per cent for incidentals, 15 per cent for clothing, 9 per cent for other expenses, and loses in various ways 50 per cent of the amount then remaining. What sum does he have left ? Percentage. 237 7. What per cent of a school is boys, and what per cent girls, there being 640 of the former and 560 of the latter ? 8. What per cent of 9.075 is 24.2 ? 9. How large a sale must a merchant make, at a profit of 15 %, that his gain may be % 3750 ? 10. A coal dealer bought 25,784 tons of coal at % 5 a ton. He sold 40% of it at % 7, 20% of it at $8.50, and the remain- der at % 4.50. How much did he gain ? 11. A man shipped 600 barrels of flour, and lost 16f% of it by storm ; he sold 75% of the remainder. What per cent of the whole remained ? 12. 66f % of 200 bushels is 2£% of how many bushels ? 13. If corn selling for 21^ a bushel more than cost gives a profit of 30%, what did it cost? 14. \ + I of a number is what per cent of it? 15. A boy deposited $ 15 in bank. This was 30 per cent of what he had in bank before making this deposit. What had he there after this deposit ? 16. A man can do a certain work in 18f days. What per cent of it can he do in 6| days ? 17. A man spent 30 per cent of his money for clothes, 20 per cent for rent, and had $ 75 left. What rent did he pay ? 18. What is the difference between £ per cent of $ 15,000 and 50 per cent of $ 15,000 ? 19. A pole extended into the mud 5f feet; 33^% of its length was in the river and 25% of it in the air. What was the length of the pole ? 20. There were 984 patients in a certain hospital, classi- fied as follows : 369, pulmonary diseases ; 246, nervous dis- eases ; 123, diseases of heart ; and 246, various other diseases. Give the per cent of each class. 238 Chapter Five. APPLICATIONS OF PERCENTAGE. 313. Commission. — The term per cent occurs in many- business transactions. A person who sells goods for another receives a certain per cent of the amount he obtains for the goods, as a commission. A person who buys goods for another is paid a commission, which is a certain per cent of the cost of the goods. A person who collects money for another is paid a commission of a certain per cent of the amount collected. Commission is a percentage paid to an agent for his services. 314. Insurance. — The owner of property who desires to be insured for a definite sum pays some per cent of this sum for the insurance. The amount he pays is called the premium. The document given by the insurance company as a receipt is called a policy. It states the agreement of the company to pay the owner of the property a sum equiva- lent to the loss sustained, provided that it does not exceed the sum for which the owner is insured. Thus, the owner of a house valued at $ 5000 may insure it against fire for $4000. If the house is injured to the extent of $4000 or less, the owner receives from the company the amount of the loss. Insurance is a contract by which one party agrees to pay to another a specified sum in case of loss or damage. Note. — The teacher should show pupils an insurance policy, and read the contract made by the company as expressed therein. 315. Duties. — The United States government collects from the importers of certain classes of goods a stated percentage of the value of the goods. This charge is called a duty. Duties are taxes on imported goods. Note. — Some duties are based upon a certain rate per square yard, per pound, etc. Applications of Percentage. *39 316. Taxes. — For the expenses of maintaining a city, property owners pay a certain percentage of the valuation of their property as determined by the proper officials. The money thus collected from the owner is called a tax. The value fixed by the authorities is called the assessed value, which is generally somewhat less than the actual value. A tax is a sum of money levied on persons or property for public purposes. Note. — In many places the tax rate is fixed at so many thou- sandths of the assessed value. The following ten oral and twenty written problems in- volve no new principles. The general formula b x -^- =p is applicable to each of them. The accompanying statement shows the base on which the percentage is calculated in certain classes of examples; also the name given to the percentage. Base JYalue of goods bought [ or sold, etc f Sum for which property is insured .... Assessed value of prop- erty Duties .... Value of goods imported Duty Commission . Insurance Taxes Percentage Commission Brokerage Premium Taxes 317. Oral Problems. 1. An agent collected a bill, and sent to his employer the amount, less 2J% commission. If his commission was $ 1.60, how much did he remit to his employer ? 2. My house, worth $ 12,000, is insured for J of its value, at \°lo' What premium do I pay ? 24° Chapter Five. 3. A man collected a bill of $ 300 for me, at |% com- mission. How much was his commission ? 4. Mr. Eastman collects bills for me, and I pay him 12 J%. He pays over to me §56. How much did he collect ? 5. What is the premium for insuring $ 3600 on my house at |% ? 6. What will it cost to insure a house worth $ 5000, at \°/o premium ? 7. Eind the duty at 35% on goods valued at $ 2000. 8. My taxes for 1904 are $ 175. The rate is If per cent. What is the assessed value of my property ? 9. My agent collects the yearly rent of my house, and retains $ 15, the amount of his commission at- 2\ per cent. Eor how much does the house rent per year ? 318. Written Problems. 1. How much insurance does a man receive for $ 12.50 when the rate is 2|% ? 2. An importer paid duties amounting to $386.75. If the duty was 25% of the cost of the goods, what was their cost? 3. A collector deducts 2J% commission, and returns to his employer $ 745.68. How much did he collect ? Let x represent the sum collected. Then 2£% of se, or — , will repre- of) ~ 40 sent the commission ; and x , or -^—, will represent the amount returned to the employer. ^ = 745.68. 40 Clearing of fractions : 39s = 29,827.20. a; = 764.80. Ans. $764.80. It will be noted that only abstract numbers are used in an equation, the denomination being supplied in the answer. Applications of Percentage. 241 4. The tax rate of a certain city is lf% upon the assessed value of property. If this value is 75% of the actual value, how much taxes does Mr. Smith pay upon a house and lot, the actual value of which is $ 24,000 ? 5. The tax on an assessment of $8500 is $48.45, Eequired the rate on $ 1000 of assessment. 6. Find the amount of an agent's sales, when his com- mission at 5 per cent amounts to $ 37.65. 7. An agent buying wheat is offered a commission of 4^ per bushel, or one of 4^- per cent, and he chooses the former. The average price paid per bushel is 91^. Does he gain or lose by his choice, and how much per bushel ? 8. A commission of $121.29 was charged for selling $ 1866 worth of goods. What was the rate of commission ? 9. A man insured his house for $ 6500, his store for $3500, and his goods for $7000, at £%. What did his insurance come to? 10. If a piece of property is taxed $ 28.60, at a tax rate of -f of one per cent, what is the assessed value of the property ? 11. A house valued at $ 24,000 was insured for two-thirds of its value, at f %. What is the premium ? 12. An agent collected 20% of an account of $ 750, charg- ing 4% commission. What was his commission, and what sum should he have paid over ? 13. Paid $27 for an insurance policy on my house. If the rate is f %, for how much is my house insured ? 14. My agent collected 80 per cent of a debt of $ 4500, and charged 1\ per cent commission. What amount should he pay me ? 242 Chapter Five. 15. A farmer bought 6 cows through an agent. He sent $ 525.30 to pay for the cows and a commission of 3%. How much did each cow cost ? 16. What will be a broker's commission, at 2|%, for sell- ing a farm of 673 acres @ $52 per acre ? 17. If the tax rate is $13.80 on $1000, what is the assessed value of property that pays a tax of $ 144.90 ? 18. A house is insured for -| of its value at -J%. The annual cost (premium) is $ 8.40. What is the value of the house ? Let x represent the value. Then — ^ x — , or — — , will represent 4 . . 3 800 1200 the premium. 7 x The equation becomes — — = 8.40. 19. What will be the taxes on a house worth $48,000 and assessed at -| of its value, the tax rate being $ 18.50 per $ 1000 of assessed value ? 20. A commission merchant receives 2\°fo commission for buying grain for a customer. The cost of the grain and his commission amount to $ 4223. How much does the grain cost? Let x represent the cost of the grain ; — will be the commission. 21. An importer paid $134.40 duties on imported goods valued at $ 384. Find the rate. 22. What is the duty in United States money on glass ware valued at 1500 francs, the rate being 60%, and the franc being worth 19.3 cents ? 23. Find the duty on a gross of scissors, valued at $2.50 per dozen, the rate being 75 cents per dozen and 25% on the value. Profit and Loss. 243 PROFIT AND LOSS. In determining the rate per cent of gain or loss on goods sold, the buying price of the goods is taken as the base. 319. Oral Problems. 1. What is the gain per cent on sugar bought at 5 cents per pound and sold at 6 cents per pound ? Profit \f, which is one-fifth of buying price, or 20%. 2. By selling a house for $ 3500, 1 lose $ 500. What is my loss per cent ? The loss, $ 500, is what per cent of the cost, $ 4000 ? 3. By selling a lot for $ 1000, Mr. Jones loses 20 per cent. What did the lot cost ? The selling price, $ 1000, is four-fifths of the cost. 4. Find the cost of an article which was sold for $ 60, at a loss of 70%. 5. If I buy a dozen pencils at 2^ each, and sell at 3fi each, what is the gain per cent ? 6. A saddle was sold for $ 18, which was 12 J- % more than the cost. How much did it cost ? 7. What % is gained on goods sold at double the cost? 8. Sold flour at a profit of $ 2, and gained 25 a • a 1 m ^ ns - 43 yd- 2 in. Write the remainder in the column of ■* inches and 129 ft. to the left of 1550 in. Reduce 129 ft. to yards, writing the result, 43 yd., as shown above, and cancelling 129 ft. 363. "Written Exercises. Change : 1. 4530 feet to rods, yards, etc. 2. 6324 yards to miles, rods, etc. 3. 244 pints to bushels, pecks, etc. 4. 467 quarts to bushels, pecks, etc. 5. 923 pints to gallons, quarts, etc. • 6. 785 pints to gallons, quarts, etc. 7. 543 pennyweights to pounds, etc. 8. 175 grains to pennyweights, etc. 9. 625 pence to pounds, shillings, etc. 10. 836 shillings to pounds, etc. 11. 8423 min. to days, hours, etc. 12. 2348 inches to yards, etc. ADDITION OF DENOMINATE NUMBERS. 8 in. + 10 in. + 5 in. = 23 in. = 1 f t 11 in. Write 11 in. and carry 1 ft. 1 f t. + 1 ft. + 2 f t. = 4 f t. = 1 yd. 1 ft. Write 1 ft. and carry 1 yd. 16 yd. 1ft. 11 in. Ana. 1 yd. +4 yd. + 11 yd. = 16 yd. Write 16 yd. 364. Find the sun Hyd. 2 ft. 8 in. 1ft. 10 in. 4 yd. Oft. 5 in. 28o Chapter Five. 365. Written Exercises. Find sums : 1. 8 mi. 44 rd. 3 yd. 4. 243 gal. 2 qt. 1 pt. 6 mi. 298 rd. 4 yd. 168 gal. 3 qt. 1 pt. 67 rd. 1 yd. 1 qt. 1 pt. 27 rd. 3 yd. 2 ft. 5. 4 1b. 10 oz. 14 pwt. 3rd. 2 yd. 1ft. 3 1b. 9oz. 16 pwt. 78 rd. 4 yd. 2 ft. lib. 11 oz. 7 pwt. 8bu. 3pk. 5qt. 6. 8 oz. 9 pwt. 21 gr. 16 bu. 2pk. 3qt. 3oz. 11 pwt. 6gr. 4bu. 3pk. 7qt. 17 pwt. 23 gr. •3. SUBTRACTION OF DENOMINATE NUMBERS. From 35 yd. 1 ft. 4 in. Since 8 in. is greater Take 19 yd. 2 ft. 8 in. than 4 in -> w © must use 15 yd. 1 ft. 8 in. Ans. l ft ' 4 ,n - or 16 in " M the minuend. 16 in. — 8 in. = 8 in. As the minuend now contains ft., 1 yd. is taken from 35 yd. Changing the yard to 3 ft., and deducting 2 ft., leaves 1 ft, U yd. - 19 yd. = 15 yd. 867. "Written Exercises. Find differences : 1. 183 rd. 4 yd. 68 rd. 5 yd. 1ft. 2 ft. 2. 91 mi. 83 rd. 26 mi. 122 rd. 2 yd. 4 yd. 3, 3 pk. 1 qt. 1 pk. 4 qt. 1 pt. 4. 29 gal. 2 qt. 28 gal. 3 qt. 1 pt. 5. 6. 8 1b. 6 1b. 3 oz. 8 pwt. 8 oz. 10 pwt. £24 £3 6s. 3d. 9s. Sd. Denominate Numbers. 281 MULTIPLICATION OF DENOMINATE NUMBERS. 368. Multiply 34 yd. 2 ft. 9 in. by 7. 244 yd. 1 ft. 3 in. 7 times 9 in. = 63 in. = 5 f t. 3 in. Write 3 in. 7 times 2 ft. = 14 ft. Carry 5 ft., making 19 ft., or 6 yd. 1 ft. Write 1 ft. Multiply 34 yd. by 7, adding in 6 yd. when the 4 is multiplied. 369. Written Exercises. Find products : 1. 6 mi. 24 rd. 4 yd. by 9. 6. 3 gal. 1 qt. 1 pt. by 32. 2. 36 rd. 4 yd. 2 ft. by 12. 7. 8 lb. 4 oz. 12 pwt. by 10. 3. 24 bu. 3 pk. 6 qt. by 14. 8. 16 oz. 12 pwt. 20 gr. by 4. 4. 2 pk. 3 qt. 1 pt. by 36. 9. £4 12s. 6d. by 20. 5. 11 gal. 2 qt. 1 pt. by 8. 10. £28 16s. 9d. by 7. DIVISION OF DENOMINATE NUMBERS. 370. Divide 244 yd. 1 ft. 3 in . by 7. 34 yd. 2 ft. 9 in. Ans. The quotient of 244 yd. divided by 7 is 34 yd., with a remainder of 6 yd. Reducing 6 yd. to ft. and adding in 1 ft., the dividend is 19 ft. 19 ft. 4- 7 = 2 ft. with 5 ft. remainder. 5 ft. 3 in. = 63 in. 63 in. -*- ? = 9 in. 371. "Written Exercises. Find quotients : 1. 44 mi. 124 rd. 2 yd. by 8. 2. 14 yd. 1 ft. 9 in. by 21. 3. 37 bu. 1 pk. 2 qt. by 6. 4. 12 bu. 3 pk. 6 qt. by 18. 5. 7 gal. 3 qt. 1 pt. by 3. 282 Chapter Five. 6. 3 gal. 1 pt. by 5. 7. 28 lb. 10 oz. 16 pwt. by 24. 8. 4 oz. 10 pwt. 3 gr. by 9. 9. £ 24 l»7s. 4d. by 16. 10. £ 3 7s. 6d. by 10. 372. Divide 244 yd. 1 ft. 3 in. by 34 yd. 2 ft. 9 in. In dividing one concrete number by another concrete number, the divisor and the dividend must be of the same denomination. Thus, to divide $ 2 by 25^, we change the dividend to cents, 200 cents -f- 25 cents, or the divisor to dollars, $ 2 -f- $ \. • The quotient is 8, an abstract number ; that is, 25 cents is contained in 200 cents 8 times. 244 yd. 1 ft. 3 in. = 8799 in, ; 34 yd. 2 ft. 9 in. = 1257 in. 8799 in. -T- 1257 in. = 7, Ans. The result would be the same if we divided 733£ ft. by 104£ ft., or 244& yd. by 34H yd. 373. Written Exercises. Find quotients : 1. 4 mi. 36 rd. 1 yd. by 6 rd. 3 yd. 2. 88 rd. 2 yd. 2 ft. by 8 rd. 4 yd. 2 ft 3. 21 bu. 2 pk. 4 qt. by 1 bu. 3 pk. 4 qt 4. 15 bu. 1 pk. by 3 pk. 6 qt. 1 pt. 5. 60 gal. 1 pt. by 4 gal. 2 qt. 1 pt. 6. 16 gal. 3 qt. 1 pt. by 2 qt. 1 pt. 7. 17 lb. 11 oz. 10 pwt. by 8 lb. 11 oz. 15 pwt. 8. 1 lb. 2 oz. 18 pwt. by 3 oz. 14 pwt. 12 gr. 9. £24 16s. 8d by £18 12s. 6 writing the first figure in the units' place. 2736448 11. 4008 x 214 16. 6352 x 927 12. 8736 x 742 17. 2781 x 525 13. 3764 x 327 18. 9060 x 1166 14. 1087 x 848 19. 6329 x 618 15. 8319 x 416 20. 2345 x 1272 21. Multiply 6984 by 25. ± of 698400. 22. 4327x75 23. 3762 X 62%. Multiply 376,200 by f 24. 5796 x 62£ 27. 7154 x 87£ 25. 8383 x 12£ 28. 6419 x 33J 26. 3428 x 37J 29. 6208 x 66$ 292 Chapter Five. REVIEW OF FRACTIONS. 384. "Written Exercises. 7854 xf 9365 xf 1963£ Deduct J. 1170| Deduct f 5890J Ans. 8194f ^tis. Multiply 6578 by 9|. 65,780 = 10 times number. 2,192} = i number (deduct). 63,587J Ans. 385. Find products: 1. 176 x H 11. 4844 x9£ 2. 273 x H 12. 8960 x 8J 3. 4554 x £ 13. 3245 x 7J 4. 1001 X ff 14. 9060 x 11£ 5. 3243 x i 15. 658 x 99£ 6. 6776 x | 16. 658 x 99f 7. 2307 x £ 17. 725 x 119| 8. 7284 x J 18. 347 x 79f 9. 5631 x A 19. 418 x 89£ 10. 9657 x H 20. 543 x 49J 386. Written Exercises. Note. — Do not use too many figures. 1. Add£,2i,f f. 2. Divide each of the following fractions by 6 : 3. Keduce J- of -jSj- of -fa of 2-J to a simple fraction. 4. 38$-21|f 40$ -18$ Review of Fractions. 293 5. What fraction of £ 1 18s. 9d. is 5s. 6d. ? 6. Multiply 24£ by f of f 7. What is the greatest common divisor of 657 and 1168 ? the least common multiple of 12, 16, 20, 30 ? 8. What must be taken. from 8^ to leave 3^ ? 9. Eeduce fff.and Mf to their lowest terms. 10. Which is the greatest and which is the least, -J- of ^, -J of f, and 2i of -ft? 11. What must be added to 3ft- to make 5f ? 12. Add f of a week, f of an hour, ft- of a minute. 13. How much is 9 times each of the following fractions? ™„ o „ - ** TT' «* tr 14. 3 and. y$ Jfo- as a decimal. 14. 3.009 x .07 x .0907. 15. Divide .0075 by .15, and .00044408 by .0112. 16. Divisor, 403.6 ; quotient, 2.709. Dividend ? 17. What is the value of ° 35 * QQ56 ? .00007 18. Change 69 rods to the decimal of a mile. 19. Change .4285 month (30 days) to days, hours, etc. Special Drills. 295 SPECIAL DRILLS. 388. Give sums: 1. 856 + 256 = 856 + 200 + 50 + 6 The pupil says (or thinks) only 1056, 1106, 1112. 2. 576 + 425 4. 749 + 312 6. $6.73 + $3.94 3. 685 + 599 5. 567 + 658 7. $8.27 + $4.89 Give remainders : 8. 1244 - 655 = 1244 -600-50-5 Think only 644, 594, 589. 9. 1021-576 11. 1040-312 13. $12.00 -$8.73 10. 1264-685 12. 1322-643 14. $11.05 -$2.69 Give products : 15. 24 x 21 = 20 times 24 + 24 = 480 + 24 Say only 480, 504. 16. 33 x 21 18. 41 x 41 20. 31 x 31 17. 22x31 19. 32x41 21. 44x21 Give sums : 22. 425 + 99 = 425 + 100-1 Say only 525, 524. 23. 576 + 99 24. 999 + 425 25. $8.68 + $4.99 Give remainders : 26. 565-99 = 565-100 + 1 Say only 465, 466. 27. 743-99 28. 1230-999 29. $12.13 -$4.99 Give products : 30. 27x99 = 100 times 27 -27 = 2700 -27 31. 36x99 32. 24x99 33. 98x99 2<)6 Chapter Five. 389. Oral Eeview Problems. 1. What will be the cost of 48 yards of cloth at 87-^ per yard? 2. A horse was sold for $ 80, which was J of the cost. How much was lost on the horse ? 3. How many yards of carpet 27 inches wide will be needed to cover a floor containing 48 square yards ? 4. Paid $3.45 for groceries, $1.50 for dry goods, and 99 ^ for sundries. What is the total ? 5. From a chest containing 25 J pounds of tea, 8£ pounds were sold. How many pounds remain ? 6. What would be the cost of 2 bushels blueberries at 5^ per quart? 7. 83 J yards of cloth are divided into 9 pieces. How many yards are there in each piece ? 8. I buy hardware to the amount of $6.37. I give the storekeeper two $5 bills. How much change should I receive ? 9. What will be the cost of 24 yards of calico at 4|^ per yard? 10. What should I pay for 19 baseballs at $1.25 each? 11. At $ 1.87-J per yard, what will be the cost of 120 yards of silk ? 12. For $120, how many yards of silk can I buy at $1.87£ per yard? 13. What is the interest of $300, for 30 days, at 6 per cent? 14. What will 18 oranges cost at 35^ per dozen ? 15. At 4f ^ per yard, how many yards of calico can I buy for 95^? Review. 297 16. How many square yards are there in a field 41 yards long, 42 yards wide ? 17. If I pay 15^ for 3J yards of muslin, what is the price per yard ? 18. How many acres of land are there in two farms con- taining, respectively, 347 and 495 acres ? 19. At 87£^ each, how many baseballs can be bought for $56? 20. How much will be paid for 21 pounds butter, at 28/ per pound ? 21. Paid 23/ for calico, 27/ for ribbon, and 48/ for collars. What was the amount of my bill ? 22. A farmer had 95 sheep. He sold 39, and 17 died. How many had he left ? 23. What will be the cost of 16 baseballs, at 49/ each ? 24. How much paint will there be in 27 casks, each con- taining 75 pounds ? 25. A man divided a 429-acre farm into plots of 13 acres each. How many such plots were there ? 26. There are 900 men in a certain regiment. How many companies of 75 men each are in the regiment ? 27. Find the cost of 136 pounds sal-soda, at \j per lb. 28. At 19J/ per yard, what will be paid for 64 yards gingham ? 29. How many square inches in a sheet of paper 10-J- inches long by 4£ inches wide ? 30. If 2| yards of cloth are needed for a jacket, how many jackets can be made from 18| yards? 31. How many yards around a field 96 yards long, 75 yards wide ? 298 Chapter Five. 32. What will be the area, in square rods, of a triangle 33 rods base, altitude 42 rods ? 33. How many acres in 4960 square rods ? 34. How many feet in a mile ? 35. I paid $16.25 for cloth at $1.25 per yard. How many yards did I buy ? 36. Half a number -f ^ of the same number = 85. What is the number ? 37. I mix 4 pounds of coffee costing 20^, with 6 pounds costing 25^. What is the mixture worth per pound ? 38. A tailor makes up 99 yards of cloth into trousers, using 2| yards per pair. How many pairs of trousers does he make ? 39. At 60^ per pound, what will be the cost of a chest of tea weighing 45 pounds ? 40. A man owns a strip of land with a frontage of 576 feet. How many lots 18 feet front can he make ? 41. A can do a piece of work in 5 hours, B in 7 hours. How long will it take both working together ? 42. At what rate will $ 300 gain $ 24 in 2 years ? 43. What sum of money will gain $30, in 2 yr. 6 mo., at 6%? 44. If a staff i2 feet long casts a shadow of 3 feet, what is the length of a pole that casts a shadow of 27 feet at the same time ? 45. If 20 men can perform a piece of work in 8 days, how many men will it take to do the same work in 5 days? 46. An agent receives $8200 to invest after deducting his commission of -fa of the amount invested. What is the agent's commission? 47. A lot is sold for $1200, at a loss of 20 per cent What part of $ 1200 is the loss ? Review. 299 390. Written Problems. 1. A rug costs $ 20. It is sold at a profit of 20%. The selling price is 20% below the marked price. How much is received for the rug ? What is the marked price ? 2. What price must cloth, which cost $ 2 per yard, be marked so that a profit of 20 % will be made when the cloth is sold at 20 % less than the marked price ? 3. A coal bin is 6 feet long and 4 feet wide. How deep must it be to contain 5 tons of stove coal, if one ton occupies 36 cubic feet of space ? 4. A man walking at the rate of 3 mi. 96 rd. per hour will walk how far in 3 hr. 16 min. ? 5. If a merchant pays 6\tf per yard for muslin, and sells the same for 7\ $ per yard, what is his gain per cent ? 6. Make and solve a problem illustrating the application of percentage to the finding of an agent's commission. 7. Multiply eight hundred (units) and forty-six ten- thousandths by three thousand forty millionths. 8. What is the interest on $ 128.40, for 1 yr. 5 mo. 17 da. at 6 per cent ? 9. A regiment of 940 men, during the war, lost 532 of their number by death and 125 by desertion. What was the percentage of loss in each case, and what per cent remained for service ? 10. A merchant sold a lot of damaged sugar at a loss of 25 per cent, receiving $ 1972.65. How much did the sugar cost him ? 11. What is a pile of wood 15 feet long, 10£ feet high, and 12 feet wide worth, at $ 4^- per cord ? (1 cord = 128 cu. ft.) 12. Add the greatest and the least of the three fractions H> h if 5 an ^ divide the sum by the remaining fraction. joo Chapter Five. 13. Multiply 82 ten-thousandths by 7 and 5 hundredths, and divide the product by 705 millionths. 14. Find the cost of 96 feet of pine lumber at $ 25 per M, and 1650 laths at $ 3 per M. 15. A horse costing $ 160 is sold for $ 180. What is the gain per cent ? What is the loss per cent when a horse costing $ 180 is sold for $ 160 ? 16. A merchant sold 600 barrels of flour for $ 3450, at a loss of 4J per cent. What did the flour cost him per barrel ? 17. How long would it take a person to count a million silver dollars, at the rate of 100 a minute, and working 8 hours a day? 18. Find the number of days from March 2, 1903, to August 11, 1903. 19. Find the interest on a note for $ 250, dated Jan. 21, 1904, and paid May 30, 1904, at 6 %. 20. Divide 22.5 by 51.75, and express the result in the form of a fraction. 21. By the census of 1890, the population of a certain city was 26,275. By the census of 1900, its population was 31,530. Find the per cent of increase. 22. Each of two boys bought 100 apples for a dollar. The first boy sold his, 4 apples for 5^ ; the second sold his, 5 apples for 6$. Which boy gains the more per cent? How much more ? 23. A quantity of coal was bought for $900. For what must it be sold to gain 33J % ? 24. By selling a house for $5760, a man gained on the cost 25 %. What was the cost ? 25. Change to other methods of expression, J, -J-, .37^, J, .16J. Review. 301 26. A note of $ 1260, dated July 5, 1904, was paid June 7, 1906, with interest at 8%. What was the amount paid ? 27. A flock of sheep has been increased by 250% of its number, and now numbers 1050. What was the original number ? 28. Bought a house for $ 6240, and sold it so as to gain 35%. What did I sell it for ? 29. Sold goods at a loss of 20%, an actual loss of $ 57.50. What was the first cost ? 30. The milk from a herd of 25 Jersey cows, sold at 6 $ a quart, amounted in one summer to $2025. How many quarts were sold, and what was the average quantity from each cow ? 31. A woman has three children. She pays for each $ 15 a year for having his clothes made, $ 1.50 a month for his mending, and $ 0.35 a week for his washing. How much could she save in a year if she knew how to wash, make clothes, and mend ? 32. A farmer exchanged 340 bushels of corn worth 75^ per bushel, for barley worth $ 1 per bushel, and oats worth 50 ^ per bushel. How many bushels of each did he receive, the quantity of barley and oats being equal ? 33. A pole stands \ in the mud, f in the water, and 32 ft. in the air. How long is the pole ? 34. Bought flour for $ 8.25, and sold it for $ 9. What is the per cent of gain ? 35. Bought flour for $ 9 and sold it for $ 8.25. What is the per cent of loss ? 36. If two-thirds of a yard of silk can be bought for $f, how many yards can be bought for $ 3| ? 37. A drover sold 250 sheep for $1150, which was 15% more than they cost. What was the cost of each sheep ? 302 Chapter Five. 38. Find a common divisor of 72 and 90. 39. How many feet of paper, 18 inches wide, will paper the sides of a room 16 feet by 14 feet, and 10 feet high, de- ducting 174 square feet for doors and windows ? 40. Find the sum of fa $, f§, -^, ^-, in decimals, correct to fourth place. 41. The dividend is 9876, the quotient is 87, the remain- der is 45. Find the divisor. 42. Change .03125 to a common fraction in smallest terms. 43. Bought a hogshead of sugar containing 848 pounds for $ 38.16, and paid $ 4.24 freight and cartage. At what price per pound must it be sold to gain 20 % ? 44. To f of f add \ of fa, and reduce to lowest terms ; multiply the sum so obtained by If, and reduce to a mixed number ; from the product subtract f , and reduce to lowest terms ; divide the remainder by 5, and convert the quotient into a decimal fraction; add 1.1 ; multiply by 2.5; subtract .9 ; and divide the remainder by .007. 45. A can weigh a certain quantity of goods in 15 days by working 7 hours a day. How long will it take him to do the same work by working 9 hours a day ? 46. In an example in division the remainder is 14, the divisor is 16, and the quotient is 18. What is the dividend ? 47. Solve by cancellation : How many pieces of cotton cloth, each piece containing 42 yards, at 9-J- ^ per yard, can be bought for 14 firkins of butter, each containing 56 pounds, at 19^ per pound ? 48. What must be the depth of a bin which is 4 ft. wide and 6 ft. long, to contain 40 bushels oats ? 49. A farmer sold 9875 pounds hay at $ 12£ per ton, and took in part payment 5000 feet of boards at $11 per thousand. How much remained due him ? Review. 303 50. Bought 80 barrels of flour at $ 6 per barrel, paying for freight $ 30. At what price must I sell it per barrel to gain 30 % on the total cost ? 51. What is the amount of $ 720.50, for 3 yr. 5 mo. 19 da., at 6 per cent ? 52. Three men buy a house for $ 2500. A pays $ 500, B pays $ 900, C pays f 1100. They rent it for $ 250. What is each one's share of the rent ? 53. If 12.875 acres of land cost $ 1030, what will 4.75 acres cost ? 54. Write three-fourths of one per cent, first as a pure decimal, and again as a common fraction. 55. If a man paid $18f for a load of hay weighing 1£ tons, what would he pay at the same rate for f of a ton ? 56. If 11 weavers in 9 days weave 1584 yards, what will 1 man do in 1 day ? 6 men in 7 days ? 57. What is the exact interest of $ 500, for 100 days, at 8 per cent ? (Take 365 days to the year.) 58. Divide the product of 8| and llf by their difference. 59. A merchant bought 340 bushels of potatoes at 80^ per bushel ; 20 per cent of them proved worthless, and were thrown away. He sold the remainder at $ 1.10 a bushel. What did he gain or lose ? 60. Divide eighty-four and eighty-four hundredths by forty-eight thousandths. 61. How much money in silver dollars, 41 2 J- grains each, will weigh 165 pounds Avoirdupois, 7000 grains to the pound ? 62. What is the amount of f 1395, at 4 per cent, for 7 mo. 24 da. 63. A coal dealer buys 150 tons of coal, 2240 pounds each, at $ 4.50 per ton. He sells it at f 4.75 per ton, giving 2000 pounds to the ton. What is his profit ? 304 Chapter Five. 64. What is the value of (J of f of 3f +8£)-^(10£-7f£) ? 65. How many bushels of grain will fill a bin 8.5 feet long, 4.25 feet wide, and 3| feet deep ? 66. Three workmen receive $ 283.50 for doing a piece of work. One worked 32 days, the second worked 53 days, the third worked 41 days. What is the share of each ? 67. A man bought silverware for $ 120, and sold it for $ 250 less 33£ and 10 per cent. What was his profit per cent? 68. What is the interest on f 356.75, at 4 per cent, for 3 yr. 5 mo. 14 da. ? 69. A note for $ 600, drawn Jan. 16, payable 4 months after date, is discounted March 25 at a bank, at 6 per cent. What are the proceeds ? 70. A dry-goods merchant sells goods 12J^ per yard more than their cost, and realizes a profit of 8 per cent. What is the cost per yard ? 71. A man bought 396 acres of land for $40,293. He sold 150 acres at $ 120 per acre, 134 acres at $ 80 per acre, and the remainder at cost. Did he gain or lose, and how much ? 72. If 44f yards of calico cost $ 1.99, how much must be paid for 80 yards ? 73. Divide the sum of 75 thousandths and 75 ten-thou- sandths by the difference between 75 hundredths and 75 tenths. 74. What number divided by 320 gives 47 for quotient and 163 for remainder? 75. In a schoolroom there are 35 pupils and a teacher. The room is 30 feet long, 20 feet wide, and 15 feet high. How many cubic feet of air space has each person ? 76. A merchant sold a quantity of flour for $ 282, losing 6 per cent. How much money did he lose ? Review. 305 77. I bought 2500 bushels of wheat at 80^ per bushel, and sold it for 84 f per bushel, on a note for 60 days, which I had discounted immediately at a bank, at 6 %. How much did I gain ? 78. A merchant bought 84 yards of linen at 55^ per yard, and 105 yards of muslin at 20^ per yard. He sold all the linen at 40^ per yard. What must he charge per yard for the muslin in order to make up exactly his loss on the linen ? 79. A fruit dealer bought a lot of oranges for $ 240. He sold \ of them for \ of the entire cost ; \ of the remainder for I of the entire cost ; \ of what then remained for \ of the entire cost ; and the final remainder for \ of the entire cost. What was his gain or loss? 80. The owner of 165 shares of gas stock sold them at $ 25 per share, and with the proceeds purchased two lots, 32 feet by 115 feet, and 30 feet by 105 feet, respectively, and had just $ 27 left. What was the price per square foot of the lots? 81. *A man purchased a house, paying for it in four pay- ments as follows : on the first payment \ of the purchase price; on the second payment \ of the remainder; on the third payment f of what then remained due; and on the last payment $ 2000. What was the full amount paid for the house ? 82. Find the difference between the greatest common divisor of 480 and 520, and the least common multiple of 5, 6, 15, and 20. 83. Find the value of a pile of wood 40 feet long, 8 feet wide, and 4 ft. 6 in. high, at $5.50 a cord. 84. A cargo of flour was bought for $690. For what must it be sold to gain 66f % ? 85. Find the sum of all the prime numbers to 50. 306 Chapter Five. 86. If A and B can mow a field in seven days, and A, B, and C mow it in five days, for $ 25, what ought C to receive ? 87. To f of a score add f of a dozen, and from the sum subtract f of a hundred. What is the remainder ? 88. What must be the length of a load of wood that is 4 feet wide and 5 J feet high to contain 2 cords ? 89. Bought a hogshead of molasses containing 128 gallons, at 65 $ a gallon ; paid 80 ^ for cartage, and lost 16 gallons by leakage. At what price per gallon must the remainder be sold to gain one-fifth of the entire cost ? 90. What is the least number that will exactly contain 48, 20, 21, 24 ? 91. Sold 50 sofas for $2250. 25 of them were sold at a gain of 20 per cent, and 25 at a loss of 20 per cent. What was the gain or loss on the transaction ? 92. Bought a number of eggs, and sold 11 of them for what 18 cost me. What was my gain per cent ? 93. A bookseller wishes to mark up the price of a book which he is now selling for $2, so that he can deduct 15 per cent, and yet receive the present price. What must be the marked price ? 94. What is the difference between .75 divided by 75, and 75 divided by .75 ? 95. A watch that loses 35 seconds in an hour was set right at noon on Monday. What time did it show at 6 p.m. the following Thursday ? 96. Mr. A. sold a horse for $ 240, which was 20 per cent less than he asked for it, and his asking price was 20 per cent more than the horse cost him. What was the cost of the horse ? 97. Three quarts dry measure is what per cent of a bushel ? Review. 307 98. What will it cost to carpet an office room measuring 21 feet in length, and 18 feet in width, the carpeting being § yard wide, and costing $ 1.35 per lineal yard ? 99. A physician accepts, in payment of a bill, a note for $275.75, due in one year and three months, with interest at 7 per cent. What amount will be due at maturity ? 100. At what rate will $1500 amount to $1684.50, in 2 yr. 18 da. ? 101. How shall I mark goods that cost me $.96 a yard, in order to abate 15% and still make 15% ? 102. What will it cost to insure a factory valued at $21,000, at£%, and the machinery valued at $15,400, at f % ? 103. In what time will $750 gain $195 interest, at 4% ? 104. What is the rate per cent when the amount of $500 is $593.75, for 2 yr. and 6 mo. ? 105. What principal will gain $360 in 5 yr. 4 mo., at 4£%? 106. Bought 480 barrels of flour, at $4.50 a barrel, and sold it for $2880. Find the gain per cent. 107. By selling a house for $10,304, a man gained 15% on the cost. What was the cost ? 108. A man, dying, left -J of his estate to his wife, § of the remainder to his son, and 'the remainder to his daughter, who received $5000. What was the value of the estate, and what was the son's share ? 109. What is the interest of $10, for 10 yr. 10 mo. 10 da., at 10 per cent ? 110. If it takes one man 1\ days to do a piece of work, how long will it take 3 men to do 2J times as much ? 308 Chapter Five. 111. A grocer pays 18^ per pound for coffee, and roasts it, losing 10% of the weight in the process. What must he charge per pound for the roasted coffee in order to make a profit of 20% ? 112. A merchant bought 48 bales of cotton, and then sold the lot for $2008.80, losing 7%. What was the cost per bale ? 113. What is the cost of sawing a pile of wood 20 feet long, 4 feet wide, and 6 feet high, at $ 1.20 a cord ? 114. After increasing the wages of his workmen 33^%, a manufacturer paid them $2.60 a day. What did he pay them before ? 115. What should a bookseller charge for a book for which he paid at the rate of $ 54 a dozen, that he may make 20% on the cost? 116. What is the per cent profit or loss when a hundred logs which cost $ 65 are sold at 78 ^ each ? 117. A man spent ^-, and invested in his business ^, of his income. He deposited the remainder, $ 1850, in a bank. What was his income ? 118. Sold a horse for $ 322, and thereby lost 8%. W T hat should I have sold it for to gain 15% ? 119. Bought a horse for $340; paid $60 for keeping him, and then sold him for $ 540. What per cent was gained ? 120. John bought Yl\ pounds of sugar at h\f a pound, spending 25% of his money. How much had he at first ? 121. When 10.25 bushels of wheat cost $ 12.71, what will 7J bushels cost ? 122. Mr. Jones paid $ 15.12 for the use of a sum of money for 1 yr. 6 mo., at 5%. What was the sum ? 123. What were the proceeds of a note for $ 725.14, due July 7, discounted at a bank June 20, at 8% ? Review. 309 124. After Mr. Jones had spent 37|% of his money, he found that he then had enough to buy 80 pounds of rice at 6i$ a pound. How much could he have bought with the whole of his money ? 125. On the 10th day of November, 1899, you lent William Rogers $ 864.50. How much does he owe you to- day, the rate of interest being 4-J % ? 126. A man bought wheat for $10,867, and sold it at a gain of 4|%. What did he receive for it ? 127. Divide three million by six thousand, and multiply the quotient by .024. 128. How much must I have invested at 5 % that my in- come may be $ 2880 per year ? 129. Add these across, placing the totals in the space in- dicated ; then add the totals : Totals. 14,305 10,702 18,346 37,946 43,865 17,387 22,324 17,437 18,438 3,741 22,972 25,960 13,849 67,431 34,965 12,674 32,905 1,468 15,607 27,865 32,476 18,430 33,301 18,695 19,898 13,460 27,686 23,492 13,852 26,973 130. If 1998, or 27 per cent, of the inhabitants of a town are voters, how many inhabitants has the town ? 131. Ten cows were sold for $ 690, at a gain of 15 per cent. For how much per head on the average should they have been sold to gain 20 per cent ? 132. Find the interest of $ 575.50, for 1 yr. 10 mo. 15 da., at 5%. CHAPTER VI. PAGES Ratio and Proportion 310 to 328 Ratio, Proportion, Partitive Proportion, Partnership, Compound Proportion. Involution and Evolution 328 to 338 Square Root, Applications of Square Root, Cube Root. Mensuration 339 to 357 The Circle, Areas of Circles, Areas of Triangles, Areas of Quadrilaterals, Surfaces of Prisms and Cylinders, Surfaces of Pyramids and Cones, Volumes of Prisms and Pyramids, Volumes of Cylinders and Cones, Sur- face of Sphere, Volume of Sphere, Circular Measure. Longitude and Solar Time 358 to 363 Standard Time, Solar Time. Review Problems 363 to 366 Miscellaneous, Oral, Written. Stocks and Bonds 367 to 372 Domestic Exchange 373 to 377 Sight Drafts, Time Drafts, Bills of Exchange. Interest 378 to 380 Compound Interest, Annual Interest. Metric System 380 to 384 Review Problems 384 to 414 Special Drills, Review of Fractions, Review of Denomi- nate Numbers, Review of Commercial Discount, Review of Interest, Review of Bank Discount, Exact Interest, Miscellaneous — Oral and Written. RATIO. 391. Ratio is the relation which one number has to another of the same kind. The sign of ratio is the colon (:). The ratio of 3 to 6 is expressed 3 : 6. The colon (:) is the sign used in France and Germany to indicate division as well as ratio. 310 Ratio. 311 ). The terms of the ratio are the numbers compared, the first being called the antecedent, and the second the conse- quent. Both terms constitute a couplet. The ratio of 3 to 6 is obtained by dividing the antece- dent by the consequent ; 3 : 6 means f , which is equal to £. 393. Oral Exercises. Find the ratio of : 1. 175 to 700. m = h Ans. 2. $ 36.50 to $ 18.25. §|^? = 2. Ans. % 18.25 Note. — The quotient is abstract. 3. 6 pecks to 5 bushels. 6 pecl f = A- Ans. Note. — The antecedent and the consequent must be like numbers, 4. 1 19 to $ 95. 6. 7 tenths to 3 fifths. 5. 20 mills to 1 dollar. 7. 3 quarts to 4 gallons. 8. 1 gallon to 500 cubic inches. 394. Written Problems. 1. One line is 3 rd. 4 yd. long; the length of another is 5 rd. 1 ft. Find the ratio of the first to the second. The antecedent 3 rd. 4 yd. is to be divided by the consequent 5 yd. 1 ft. As the divisor and the dividend must be like numbers, both terms of the couplet are reduced to feet. The 3 rd. 4 yd. = 61^ ft. _ 123 j^ division is indicated by writ- * ro -* 1 "• °3 J ft. 167 ing the antecedent above the consequent as a fraction. The concrete fraction — 2 — 1 \ s changed to 83* ft. the abstract complex fraction — , which is reduced to a simple f rac- 88| tion by multiplying both terms by 2, giving | £^ for the result. Make the antecedent and the consequent like numbers, and divide the former by the latter. 312 Chapter Six. 2. M walks in 1 hr. 47 min. as far as N walks in 2 hr. ■3 min. What is the ratio of M's speed to N's ? In this example is required the ratio of M's speed to N's. The antecedent is, therefore, M's speed, and the consequent is N's speed. As the distance walked is not given, x may be used to represent the number of feet or yards or miles walked by M in 107 minutes, and by N in 123 minutes. -^- will represent the distance walked by M in 1 minute, or M's speed, and -^- , N's speed. The ratio of M's speed to N's will be JL + JL or — x— • Cancelling x in each, the 107 123' 107 3 & result is {ffi , or 1^. Ans. 3. One candle lasts 4 hr. 20 min.; another lasts 3 hr. 15 min. Find the ratio of the first to the second. 4. A pound of coffee costs 25 J f ; 1 pound of sugar costs &A ^ What is the ratio of price of sugar to that of coffee ? 5. P earns in 19f days as much as Q in 18| days. What is the ratio of Q's daily earnings to P's ? Of P's to Q's ? 6. One wheel makes 600 revolutions in 8^ seconds; a second makes 300 revolutions in 3\ seconds. What is the ratio of the speed of the first wheel to that of the second ? 7. The circumference of a circle is 12.5664 feet, and its radius is 2 feet. What is the ratio of the diameter to the circumference ? 8. One train goes 40 miles in 50 minutes ; another goes 24 miles in a half hour. What is the ratio of the speed of the second to that of the first ? Find the number of miles each goes in an hour. 9. One window is 6 ft. 8 in. by 4 ft. 2 in.; a second is 4 ft. 8 in. by 2 ft. 1 in. What is the ratio of the area of the second to that of the first ? (4f X 2^) + (6f x H) Ratio. 3 I 3 10. A mother is now 35 years old, and her son is 3 years and 6 months old. Fourteen months ago what was the ratio of the mother's age to that of her son ? 11. A farm costing $ 4750 was sold for $ 5750. What is the ratio between the profit and the cost ? 12. A man can do a piece of work in 4^ days. What part of it can he do in a day and a half ? What decimal ? What per cent ? 13. What is the ratio between a ton of 2000 pounds and one of 2240 pounds ? 395. Oral Problems. 1. One line is a rod long; another is 5|- ft. long. What is the ratio of the first to the second ? 2. What is the ratio of 7 hours to one day ? 3. A pound of coffee costs 30^, of sugar 6^. What is the ratio of their respective prices ? 4. A walks in 4 hours as far as B in 5. What is the ratio of A's speed to B's ? 5. E earns in 6 days as much as D earns in 8 days. Find the ratio of E's daily earnings to D's. 6. One wheel makes 300 revolutions in 2 minutes ; the second requires only 1J minutes to make the same number. Find the ratio of the number of revolutions made by the first wheel in 1 minute to the number made by the second wheel in the same time. 7. A circle whose diameter is 1 foot has a circumference of 3| feet. What is the ratio of the diameter to the circum- ference ? 8. One train goes 40 miles an hour ; a second goes 45 miles an hour. What is the ratio of the speed of the first to that of the second ? 314 Chapter Six. 17 21" _51 18 _ 36 ? "70* ? 24 = 57 '72* $16 7 marks ? 21 marks 5 + 22 = ?-f-88. PROPORTION. 396. Preliminary Exercises. 1. A = l. 16 64 2 18 - 36 3. »..£ 13 65 • lj^l? ' 3bu. $24* 3qt 1 = 30^ > lgal. ?** 11. 6 horses -j- ? horses = $ 600 -r- $ 900. 12. lft. -5-? yd. = 15^-*- 90*. 13. 1 qt. lpt. -*-l pt. = ?jt + 4? 14. li+i^JH-f. 15. 2.8 -r- .4 = .14 -h #. 397. Two equal ratios form a proportion. The ratio of 3 to 9 is \, which is also the ratio of 13 to 39. This may be expressed -| = Jf , or 3 : 9 = 13 : 39. Substitut- ing a double colon (: :) for the sign of equality (=), we have the following proportion : 3 : 9 : : 13 : 39. This is read, 3 is to 9 as 13 is to 39. In the foregoing proportion, 3 and 13 are the antecedents, and 9 and 39 are the consequents. 398. The first and the last term of a proportion constitute the extremes ; the second and the third the means. In the following proportion 5:15:: 9:27 6 and 27 are the extremes, 15 and 9 are the means. Proportion. 315 The foregoing proportion may be written ft-* Multiplying each of these two fractions by the product of the denominators, 15 x 27, we have 5x ?5x27 ^ 9 x!5xgT u » Cancelling, 5 x 27 = 9 x 15. In the same way it may be shown that in any proportion the product of the numbers in the extremes is equal to the product of the numbers in the means. 399. Written Exercises. Find the missing term. 1. 3:44.-:5:z. As the product of the extremes is equal to the product of the means, 3 multiplied by x is equal to 4f multiplied toy 5 ; i.e. 3 x = 4$ x 5. jc, therefore, is equal to ? x • This reduces to ^, or 8. Ans. To find an extreme, divide the product of the means by the other extreme. 2. %:#■■ ■.*■■& The product of the means |f x X equals the product of the extremes | x J£. x is equal, therefore, to $ x || h- |£» Inverting the divisor, we have | x £J x jft. Cancel. To find a mean, divide the product of the extremes by the other mean. 3. 3% + 16 = i + x. 6. ?:19::28:76. 4. 5:7:: 121 : Xm 7. a; : 15 : : 4 : f 5. 3-*-a = 12---20. 8. a:£::2:7. 316 Chapter Six. 9. f:*::J:f 12. *fftill>**|; 10. f:f:j«:2J> 13. SB : 9 : : 4 : a;. 11. l:|::lf:aj. 14. 1 lb. 1 oz. : 2 lb. 4 oz. : : 17^ : »#. 15. 3qt. 1 pt.-r-l gal. = »^-f-80^. 16. 4 bottles : x bottles = 6 pints : 15 pints. 17. x men : 9 men = 16 acres : 36 acres. 400. Oral Problems. 1. If 9 eggs cost 25 /, what will 3 dozen cost? Explanation. — 3 dozen, or 36, will cost 4 times as much as 9 ; 4 times 25 j* = $1. 2. If 7 pounds of flour cost 23^, what will be paid for 49 pounds ? 3. For $5 1 can get 12 straw hats. How many can I get for $20? 4. A wheel makes 75 revolutions in 5 minutes. How many does it make in an hour ? 5. $100 principal gives $6 interest. How much will be the interest of $ 450 principal ? 6. A merchant pays 75^ freight on 125 pounds of mer- chandise. How much will be the freight on 1000 pounds at the same rate ? 7. A locomotive goes 3 miles in 4 minutes. How far does it go in an hour ? 8. 4 horses can eat a certain quantity of hay in 10 months. How long will it last 20 horses ? 9. 12 men can do a piece of work in 15 days. How long will 36 men require ? 10. 15 yards cost 270 cents. What will be the cost of 5 yards ? Proportion. 317 401. Written Problems. 1. If 9 cows cost $267, what will be the cost of 36 at the same rate ? The ratio of the cost, $ 267 : $ x, must be the same as the ratio of the number of cows, 9 : 36. Making the proportion, we have 9 : 36 : : 267 : x. mu t 9 267 X 36 Therefore, x = - — • 9 Cancelling, x = $ 1068. Ans. 2. 7 barrels of sugar cost $ 104.32. Find the cost of 42 barrels at the same rate. 3. A wheel makes 248 revolutions in 5 minutes. How many does it make in 1 hour 20 minutes ? Make the required number of revolutions the fourth term. The proportion will then be as follows : 5 minutes : 80 minutes : : 248 revolutions : x revolutions. _ 248 revolutions x 80 5 4. A locomotive goes 2.8 miles in 4 minutes. How far does it go in an hour ? 5. From 9 pounds of yarn are made 42 yards of dress goods. How many yards can be made from 165 pounds of yarn? How many pounds of yarn are needed for 196 yards of goods ? 6. If 17 men receive $ 357 for a week's work, how much should 24 men receive ? 7. If 17 men take 27 days to finish some work how long would it take 51 men ? Note. — The work done by 51 men would be fy of the work done by 17 men. The time required by 51 men would be £| of the time re- quired by 17 men. 3 18 Chapter Six. 8. When a sura of money is divided among 48 persons, each receives $ 27.50. How much would each receive if the same sum were divided among 16 persons ? 9. For $ 85 I can purchase 238 yards of dress goods. How many yards can I purchase for $ 5 ? 10. A can do a piece of work in 6 days ; B can do it in 7 days. If B's wages are $ 2.10 per day, how much should A receive per day ? 11. If for 7s. 6d. I can buy 9 pounds of raisins, how many pounds can I buy for £ 56 16s. ? 12. A quantity of provisions would last a ship's crew 20 days, allowing each man 2 lb. 4 oz. daily. What should each man be allowed so as to make the provisions last 4 days longer ? 24 days : 20 days : : 36 ounces : x ounces. 13. If 40 men are able to do a piece of work in 10 hours, how many extra men must be employed to finish it in 8 hours ? 8 hours : 10 hours : : 40 men : x men. The number of extra men is x-40. 14. If it requires 40 yards of carpet 2 ft. 9 in. wide to cover a floor, how many yards of carpet 2 ft. 6 in. wide would be needed ? 15. How long will it take a train to go 112 miles, at the rate of 46 miles in 1 hr. 20 min. 30 sec. ? 16. If a beam 5 ft. 6 in. long, 10 inches wide, and 8 inches thick weighs 924 pounds, find the length of another beam of the same material which weighs 3024 pounds, and whose end is a square foot. Partitive Proportion. 319 PARTITIVE PROPORTION. 402. Preliminary Exercises. 1. Coin silver consists of 9 parts silver and 1 part cop- per. What is the ratio of the weight of the silver in a dime to the weight of the coin ? 2. What is the ratio of the weight of the copper to the weight of the coin ? 3. How many ounces of copper are there in a bar of coin silver weighing 90 ounces ? How many ounces of pure silver ? 403. Partitive proportion is the process of dividing a num- ber into parts proportional to given numbers. 404. Written Problems. 1. Divide 180 into parts proportional to 2, 3, and 4. If the parts were 2, 3, and 4, the whole number would be 2 + 2 3 + 4, or 9. The ratio of the whole to the first part must be 9 to 3 2 ; of the second, 9 to 3 ; of the third, 9 to 4. These ratios give 4 rise to the proportions indicated. 9:2::180:z. .\z = 40. 9:3:: 180: y. .'.?/ = 60. 9 : 4 : : 180 : z. .'. z = 80. Ans. 40, 60, and 80. 2. Gunpowder is composed of 15 parts of saltpeter, 2 of sulphur, and 3 of charcoal, mixed together. How many pounds of each are there in 72 pounds of powder ? 15 In a mixture of 15 lb. -f 2 lb. + 3 lb., or 20 lb., there will be 2 15 lb. saltpeter; hence, the ratio of the whole weight to the 3 weight of the saltpeter is 20 lb. to 15 lb., etc. 20 : 15 : : 72 : number of pounds of saltpeter. 20 : 2 : : 72 : number of pounds of sulphur. 20 : 3 : : 72 : number of pounds of charcoal. 320 Chapter Six. 3. A bankrupt surrenders property worth $1287 for the benefit of three creditors to whom he owes $750, $1125, and $ 1245, respectively. How much should each creditor receive ? 4. A had on storage in a warehouse 2400 bales of cotton, B 1500 bales, and C 1100 bales. After a fire that destroyed all distinguishing marks, the damaged cotton was sold for $ 10,000. How should this sum be divided ? 5. Our standard gold coin consists of 900 parts gold, 90 parts silver, 10 parts copper. What is the quantity of each metal in 50 pounds of coin ? 6. Two men hire a pasture for $45. Cme puts in 15 cows ; the other puts in 12 cows. What should each pay ? 7. A and B hire a boat for 50 days, paying $30. A uses it 27 days; B uses it 23 days. How much should each pay? 8. Three farmers together paid $54 for threshing their grain. A threshed his crop of 900 bu. ; B threshed his crop of 828 bu. ; C 672 bu. What did each pay ? 9. A and B contract to haul a pile of lumber for $ 105. A furnishes 3 teams, and B 4 teams. How much does B receive ? 10. Three merchants shipped a cargo of iron by sea. A gent 180 tons, B sent 105 tons, C sent 315 tons. During a storm the sailors were obliged to throw overboard 180 tons to save the vessel. Assuming that the cargo should sustain one fourth of the loss, what portion of the loss should each merchant sustain? 11. Divide 90 into two parts which shall be to each other as 9 to 1. Partnership. 321 • PARTNERSHIP. 405. Written Problems. 1 . B and C gain by trade $ 182. What is the gain of each, B having put in $300, and C $400 ? The total investment is $ 700. The ratio of the total invest- 300 ment to B's investment is 700 to 300. This should be the ratio 400 of the total profit to B's share, etc. 700 : 300 : : $ 182 : B's share. 700:400::$182:C's share. Make proportions whose antecedents in each case are the total investment and the total profit, the consequents being the investment of one partner and his share of the profit. 2. A, B, and C invest $ 720, $ 340, and $ 960, respectively. The profits are $ 101. What is each one's share ? 3. A, B, and C buy a house for $7500. A furnishes $2000; B, $2500; C, the remainder. The yearly rent, less expenses, is $ 576. To what amount is each entitled ? 4. M and N entered into partnership. M puts $ 200 into the business for 5 months, and N $ 300 for 4 months. They gained $ 132. Find the share of each. An investment of $ 200 for 5 months is equivalent 200 x5 = 1000 to an investment of $ 1000 for 1 month ; an invest- 300 X 4 = 1200 ment of $ 300 for 4 months, to $ 1200 for 1 month. 2200 : 1000 : : $ 132 : M's share. 2200 : 1200 : : $ 132 : N's share. In ascertaining the ratio of the whole capital to the share con- tributed by each, $1000 and $1200 are taken as representing the shares of each in a total capital of $2200. Multiply each partner's share of the capital by the time it is in the busiiiess, and consider the products, respectively, as the sums contributed by the partners. Note. — This mode of ascertaining a partner's share of profits or losses is based upon the assumption that the agreement of the partners does not provide for a different division. 322 Chapter Six. 5. X and Y rent a field for $ 32. X puts in 8 horses for 6 months, and Y 10 horses for 8 months. How many dol- lars should each pay ? 8 horses for 6 months = how many for one month ? 10 horses for 8 months = how many for one month ? 6. Three men hire a pasture for $ 84. One puts in 15 cows for 12 weeks; the second puts in 20 cows for 6 weeks; the third puts in 18 cows for 10 weeks. What amount should each pay ? 7. Four men hire a pasture field together. The first pastures 4 cows 18 weeks ; the second, 5 cows 12^ weeks ; the third, 11 cows 6J weeks ; the fourth, 9 cows 16 weeks. What part of the rent should each pay ? 8. Two men hire a pasture for f 420. A puts in 300 sheep for 5 weeks, and B puts in 450 sheep for 6 weeks. What should each pay ? 9. A, B, and C enter into partnership. A puts in $500 for 4 months, B $400 for 6 months, and C $800 for 3 months ; they gain $ 340. Find each man's share of the gain. 10. A partnership is formed between A with a capital of $ 1500 and B with a capital of $ 2500. Six months there- after they take in C with a capital of $ 4000. How should a profit of $ 3500 be divided at the end of the year ? 11. A and B form a partnership. A furnishes $ 2000, B $ 3000. After a year A furnishes an additional $ 1000. At the end of 2 years the business is disposed of for $ 7100. How much should each receive ? Suggestion. — A receives his $3000 and how much of the profits ? Should he receive as much as B, who had $ 3000 in the business the whole time ? 20: :30 18: 4 :27 : 5: men men :72 : x 15: : 3 9: :10 Compound Proportion. 323 COMPOUND PROPORTION. 406. A compound proportion is one in which either ratio is compound. 407. Written Problems. 1. If 72 men dig a ditch 20 yd. long, 1 ft. 6 in. broad, 4 ft. deep, in 3 days of 10 hours each, how many men would be required to dig a ditch 30 yd. long, 2 ft. 3 in. broad, and 5 ft. deep, in 15 days of 9 hours each ? Since the number of men is required, 72 men is made the third term of the proportion. Con- sidering the length alone, the ratio of 72 men to the required number would be equal to the ratio of 20 feet to 30 feet. Considering the width, the ratio would be 18 inches to 27 inches. Con- sidering the depth, the ratio would be 4 feet to 5 feet. Considering the number of days, the ratio would be 15 days to 3 days. Con- sidering the number of hours per men day, the ratio would be 9 hours to 72 X 30 X 27 X 5 X 3 X 10 10 hours. Dividing the product of 20 X 18 X 4 X 15 X 9 the means by the product of the ex- tremes, the number of men is found to be 46. Place the number required as the fourth term, making the like number the third term. Arrange the couplets, considering the effect of each separately on the result. Divide the product of the means by the product of the extremes. 2. If 45 horses eat 1\ tons of hay in 30 days, how many tons should last 84 horses 56 days ? 3. If 4 men, working 8 hours per day, can mow a meadow in 3 days, how many men, working 9 hours per day, can mow a meadow three times as large in 4 days ? 4. If 10 men, working 8 hours per day, can build a cer- tain wall in 6 days, how many hours a day must 12 men work to build the same wall in 4 days ? 324 Chapter Six. 5. If 108 men can build a fort in 12£ days of 12 J hours each, in how many days can 84 men build it by working 10£ hours daily ? 6. What will it cost to transport 1000 pounds of mail matter 1000 miles, at $ 1 per 100 pounds per 100 miles ? 7. If 12 men can do a piece of work in 20 days, what number of men will be required to do four times as much work in a fifth part of the time ? 8. If 14 men can mow 168 acres in 12 days of 8 hr. 15 min. each, how many acres can 20 men mow in 11 days of 7 hr. 48 min. each ? 9. If 5 needlewomen can do a piece of work in 11 days of 9 hours each, how long will it take 3 needlewomen to do two such pieces, supposing them to work 10J hours each day? 10. A employs a capital of $2500 in business, and at the end of 3 years takes into partnership B, who furnishes $4000. Four years later they are joined by C, with a cap- ital of $ 5000. At the end of 12 years from the commence- ment of the business the profits, amounting to $ 15,000, are divided. What amount should each receive ? A's money is in the business how many years ? B's how many years ? C's how many ? 11. A and B rented a field for a year for $175. A put in 6 horses for the whole time; !B put in 5 horses for 11 months and 3 horses for 5 months. How much of the rent had each to pay ? 12.' A field of grain was to be cut down by 40 men in 10 days. Eight of the men, however, failed to come. How long did it take the others to do the work ? Review. 325 REVIEW. 408. Oral Problems. 1. How many weeks will 4-J- tons of coal last Mrs. Bright, if she uses ^ of a ton each week ? 2. I can buy 2 pairs of shoes for 12 shillings. How many pairs at the same rate can I buy for £ 3 ? 3. If two-thirds of your age is 8 years and 4 months, how old are you ? 4. 5 quarts equal what decimal of a peck ? 5. What is the cost of 700 pounds of coal at $ 7 a ton ? 6. How much would you pay for 2| yards of cloth at 37£ bayard? 7. In what time will f 50, at 6%, give $ 18 interest? 8. If I buy an article for $ 75 and sell it for $ 50, what is my loss per cent ? 9. By selling an article for $9, a man gained 25%. How many dollars would he have gained if he had sold the article at an advance of 50 % over cost ? 10. How many quarts of peanuts in 1 bushel and 3 pecks ? 11. What would be the cost of 120 books at 660 each ? 12. Change 66,321 mills to dollars. 13. $120 is i per cent of what number of dollars ? 14. In what time will $ 50 doubie itself at 8% ? 15. If $ 1 is paid for insuring a piano worth $ 500, what is the rate of insurance ? 16. Into how many lots, containing f of an acre each, can 8 acres be divided ? 17. A man lends $ 1200 at 6%, and 1500 at 5%. ! What is the difference in the amount of yearly interest due on each? 326 Chapter Six. 18. A man owning § of a ship sold § of his share. What part of the ship did he still own ? 19. How many rings, each 2 pwt. 12 gr., can be made from \ pound of gold ? 20. Find the number of square inches on the surface of a block 10 inches long by 4 inches wide by 3 inches thick. 409. Written Problems, 1. A traveller walked 23\ miles the first day, 3 J miles more the second day than the first, and 3J miles more the third day than the second. How far did he walk in the three days ? 2. Multiply 63.15 by 1.04; divide the product by 6.25, and subtract the quotient from 11 3. How many bricks, 8 inches long and 4 inches wide, will be needed to make a sidewalk 20 feet long and 4 feet wide? 4. If it costs $ 10.24 to carry 1500 pounds 356 miles, what will it cost to carry 2700 pounds 890 miles ? 5. A house rents for $ 30 a month, and the owner pays $ 75 a year for taxes and repairs. What is the value of the house, if his net profit is 5 per cent per annum ? 6. A loaned B a sum of money at 4£ per cent interest per annum. At the end of 18 months B paid the debt, principal and interest, in all $ 1814.75. What was the sum borrowed ? 7. If a 5-months note for $ 760, dated March 13, is dis- counted at a bank May 23, the rate being 7 per cent a year, what will be the proceeds ? 8. A grocer bought 40 gallons of maple syrup at the rate of 4 gallons for $ 6, and sold it at the rate of 5 gallons for $ 8. What was the whole gain, and the gain per cent ? Review. 327 9. Two pictures were sold for $ 99 each. On one there was a gain of 10% ; on the other a loss of 10%. Was there a gain or a loss on the sale of both, and how much ? 10. New York, Jan. 1, 1904. One year after date I promise to pay J. Edward Swans- ton Eight Hundred Dollars for value received, with interest. $800 T °oV Kufus L. Scott. Indorsed as follows: Apr. 1, 1904, $10; July 1, 1904, $35; Nov. 1,1904, $100. What was due Jan. 1, 1905 ? (Merchant's Eule.) 11. What is the difference on a bill of $780, between a discount of 40% and a discount of 35 and 5% ? 12. How many cords in a pile of wood 42 feet long, 12 feet high, and 8 feet wide ? Find its cost at $ 6.35 per cord. 13. What principal, on interest for 2 yr. 6 mo. at 4%, will gain $850? 14. What is the cost of insuring a house, worth $ 25,000, for | of its value at 1£% ? 15. At 9fi a cubic foot what will be the cost of a block of stone 9 ft. long, 4 ft. wide, and 5 ft. 6 in. thick ? 16. If a steeple 150 feet high casts a shadow of 275 feet, how long a shadow will be cast by a man 6 feet tall, at the same time of day ? 17. The tax to be raised in a certain town is $1350. The taxable property is valued at $ 108,000 What is the tax on one dollar ? 18. Mr. Fox buys one-fifth of an acre of land for $21.78. For how much a square foot must he sell it to gain 20% ? 328 Chapter Six. 19. What is the cost of covering a floor 16£ ft. long, 12 ft. wide, with oil-cloth 1% yd. wide, at 75^ a yard ? 20. The edges of a large cubical box are 5 feet long. How many square feet of paper will cover the outside of the box? 21. A field 110 yards long and 44 yards wide contains an acre. What is the area of a field 220 yards long and 88 yards wide ? Of one 440 yards long and 176 yards wide ? 110 x 44 : 220 x 88 : : 1 acre : x acres. 22. If a steel bar 12 feet long, 4 inches broad, and 2\ inches thick weighs 480 pounds, what is the weight of another steel bar 18 feet long, 3 inches broad, and 2 inches thick ? 23. At a certain hour a pole 6 feet high casts a shadow measuring 4 ft. 2 in. Calculate the height of a steeple whose shadow at the same hour is 104 ft. 2 in. 24. If 7 men receive $ 126 for 5 weeks' work, how much should they receive for 9 weeks' work ? 25. If 76 boards, each 14 feet long and 10 inches wide, are worth $19.76, how much would 50 such boards be worth ? INVOLUTION. 410. Involution is finding any power of a number. A power of a number is the product obtained by using the number a certain number of times as a factor. 2 is the first power of 2. 2 x 2, or 4, is the second power of 2. 2 x 2 x 2, or 8, is the third power of 2, etc. 411. The second power of a number is called its square; the third power is called its cube. Involution. 329 412. The power of a number is indicated by writing a small figure, called an exponent a little to the right of the upper part of a number. The square of 2 is written 2 2 . The cube of 2 is written 2 3 . The fourth power of 2 is written 2*. 5 2 = 25, 12 2 = 144. What is the square of 4 ? Of 6? Of 7? Of 9? Of 10? Of 11? Square 13. 15. 21. 16. 19. 14 2 =? 17 2 *=? 54 2 = ? 33 2 =? 413. The square of 25 = (20 + 5) x (20 + 5). 20+5 20+5 Multiplying by 20 20 2 + 20 x 5 Multiplying by 5 20 x 5 + 5 2 20 2 + 2 (20 x 5) + 5 2 = 400 + 200 + 25 = 625. 414. The square of the sum of two numbers is equal to the square of the first -f- twice the product of the first by the second -f- the square of the second. . 13 2 =(10 + 3) 2 = 10 2 +-2(10x3)+3 2 =? 18 2 = (10 + 8) 2 = 100 +• 160 +• 64 = ? 27 2 = (20 + 7) 2 = 400 + 280 + 49 = ? 415. Oral Exercises. Square : 1. 19. 4. 26. 7. 51. 10. 32. 13. 27. 2. 22. 6. 31. 8. 61. 11. 42. 14. 33. 8. 24. 6. 41. 9. 23. 12. 52. 15. 43. 23° Chapter Six. EVOLUTION. 416. Evolution is finding any root of a number. A root is one of the equal factors of a number. The square root of a number is one of its two equal factors. The square root of 4 is 2 j of 9 is 3 ; of 16 is 4 ; of 25 is 5c 417. Give the square root of 36. Of 64. Of 81. Of 121. Of 49. Of 100. Of 144. 418. The sign of a square root is -y/. V81 = 9. Vl2l = ?. V25 = ?. V49 = ?. SQUARE ROOT. 419. Find the square root of 169. 10 2 = 100. 20 2 = 400. The square root is between 10 and 20 ; it is, therefore, 10 + a second number. 169 = 10 2 + 2 (10 x second) + second 2 . 169 = 100 + 20 x second + second 2 . 20 x second + second 2 = 69. From this it appears that the second number is 3, since 20 x 3 + 3 2 = 69. 420. It may be shown in this way : 10 (first number) 169 10 2 = 100 Trial divisor — twice 10 20) 69(3 second number) 60 9 S* = 9 Ans. 10 + 3 = 13. Square Root. 331 421. Find the square root of 2116. 40 (first number) 2116 40 2 1600 40 x 2 = 80, trial divisor ) 516(6 second number) 480 36 =6 2 Arts. 46. Instead of multiplying the trial divisor by the second number, and then ascertaining whether the remainder is the square of the second number, the second number is added to the trial divisor and this sum is multiplied by the second number. In practice, the work is shortened by omitting the ciphers. 40 (first number) 4 6 Ans. 2116 21'16 1600 16 (2 x 40) + 6 = 86) 516(6 second number) 86) 516 516 516 First, point off in periods of two figures, commencing at units. Find the greatest square in the first period, and place the root in the quotient. Subtract the square from the first period and bring down the next period. Multiply the quotient figure by 2, and use it as a trial divisor. Place the second figure in the quotient and annex it also to the trial divisor. Multiply the figures in the trial divisor by the second quotient figure. Bring down the next period, and proceed as before until the square root is found. 422. "Written Exercises. Extract the square root : 1. 196. 4. 1225. 7. 2809. 10. 6889. 2. 324. 5. 1764. 8. 3721. 11. 8281. 3. 676. 6. 1936. 9. 5184. 12. 9025. 33 2 Chapter Six. 423. Find the square root : Note. — Extract the square root of each term separately. 1- jfc 4. ifr. 7. #ft. 3- itt- 6- t¥A- 9- «H» Note. — Before extracting the square root of the following, reduce the mixed numbers to improper fractions. 10. 12£. 12. 2ff. 14. 156J. 11. 11J. 13. lOfH- 15. 264 T V 424. Find the square root of 425,104 6 5 2 42'51'04 12|5 651 130|2 26 04 ^Ln«. 652. Jn finding any figure of the root after the first, we multiply the other figure or figures by 2 for a trial divisor. 425. Find the square root of 20,857,489. 4 5 6 7 20'85'74'89 8|5 4 85 90|6 60 74 912|7 6 38 89 Ans. 4567. Find the square root of 1. 64,516. 4. 71,824. 2. 73,441. 5. 141,376. 3. 18,769. 6. .702244. Square Root. 333 4. 74. 5. 350. V£6=V£60 1.89+ 3.60'00 2.8 1 2.60 2.24 3.69 .3600 .3321 426. Written Exercises. Find the square roots to two decimal places : 1. 7. 2. 14. 3. 38. 6. Find the square root of 3.6. Note. — Commence at the units and point off two places to the right as well as to the left, annexing a decimal cipher, if necessary. 7. 6.4. 8. .121. 9. .144. 10. .196. 11. .225 APPLICATIONS OF SQUARE ROOT. 427. Written Problems. 1. How many inches in the side of a square table top containing 529 square inches ? 2. The surface of a square piece of board contains 3 sq. ft. 97 sq. in. What is the length of one side in feet and mcnes . (Reduce area to square inches.) 3. How many rods long is a square field containing 90 acres ? How many yards of fence would be needed to enclose it ? 4. Land surveyors use a measure called a chain. What is its length in rodsj 10 square chains being equal to an acre ? What is the length in feet ? It is subdivided into 100 " links." Find the length of a link in inches and decimal. 5. The surface of the six equal faces of a cube is 1350 square inches. What is the length of each edge of the cube ? 334 Chapter Six. 428. Preliminary Exercises. 1. Carefully construct a right-angled triangle, base, 4 inches, perpendicular, 3 inches. Measure the hypotenuse. Take the square of the length of each side and endeavor to show the relation between the square of the hypotenuse and the squares of the other two sides. 2. Construct a right-angled triangle, base, 3 inches, per- pendicular, 1J inches. Measure the hypotenuse, and see if the relation between this hypotenuse and the other two sides of this triangle is the same as that found in the other triangle. 3. A right-angled triangle has a base 12 inches long ; its perpendicular is 3J inches. What is the length of the hy- potenuse ? 4. The hypotenuse of a right-angled triangle is 25 inches ; its perpendicular is 7 inches. What is the base ? 6. The base of a right-angled triangle is 12 feet; the hypotenuse is 13 feet. Find the perpendicular. 429. Draw a right-angled triangle (Fig. 1). Upon each side construct a square (Fig. 2). From the upper portion of the largest square (7, cut a right-angled triangle of the same /m A B Fig. 2 Fig. 8 Fig. 4 V^ B m/ Fig. 3. The two parallel faces of a prism are called its bases. The remaining faces taken together constitute its convex surface. In Fig. 1, ABC and DEF are the bases ; in Fig. 2 the bases are GHIJ and KLMN\ in Fig. 3, OPQB 8 and TUVWX. The sides AB, CE, etc., GH, IN, etc., QB, OT, etc., are called 445. Prisms may be either right or oblique. The convex surface of a right prism consists of rectangles. Fig. 1 is a right prism ; Fig. 2 is an oblique prism. Note. — When a prism is spoken of, a right prism is meant unless the word oblique is used. The altitude of a prism is the perpendicular distance be- tween the bases. AD, BF, or CE is the altitude in Fig. 1. GYis the alti- tude in Fig. 2. 446. The number of sides in each base determines the name as triangular (Fig. 1), quadrangular (Fig. 2), pentagonal (Fig. 3), etc. Surfaces. 347 A quadrangular prism whose "bases are parallelograms is called a parallelopipedon. Fig. 4 is an oblique parallelopipedon. Fig. 5 is a right parallelopipedon. Any two opposite faces of a parallelopi- pedon may be considered the bases. k \ 1 1 1 \[_ \ Fig. 4. Fig. 5. 447. When the bases are regular polygons, the prism is said to be regular. Fig. 1 is a right regular triangular prism j Fig. 2 is an oblique irreg- ular quadrangular prism. 448. A cylinder is a body having two circular parallel plane faces, and one curved face. (TZD The plane faces are the bases, face constitutes the convex The curved Fig. 6. surface. Cylinders, like prisms, are either right or oblique. The altitude of a cylinder is the perpendicular distance between the & Fig. 7. £2 Fig. & 449. Written Problems. Note. — The pupils should be encouraged to make cardboard models of the forms studied. 1. Find the convex surface of a square prism, one side of its base being 4 inches and its height 6 inches. Draw the development. Note. — The convex surf ace is the surface exclusive of the bases. 2. Find the convex surface of a triangular prism, each side of whose base measures 4 inches and whose altitude is 6 inches. Draw the development. 348 Chapter Six. 3 . Find the convex surface of an hexagonal -=^^^ prism, each side of its base being 4 inches and its altitude 6 inches. Draw the development. 4. Can you show that the convex surface of a prism is found by multiplying the perim- |||H j^J eter of the base by the altitude (height) ? 5. Find the convex surface of a cylinder, |j| ||| the diameter of its base being 4 inches and its height 6 inches. To find the convex surface of a right prism (or cylinder) multiply the perimeter (circumfer- 'llillljjj^^ ence) of the base by the height. 6. How do you find the entire surface of a prism or cylinder ? Note. — The entire surface is the surface including the bases. 7. What is the entire surface of a cube whose side is 7 inches ? Of a cube whose side is 12 inches ? 8. The entire surface of a cube is 216 square inches. What is the length of one side ? Suggestion. — Calling the length of one side L, the area of each face will be £ 2 , and of the six faces, 6 L 2 . Then, 6 L 2 = 216. 9. The convex surface of a cube is 144 square inches. Find the entire surface. How many faces in the convex surface ? 10. Find the entire surface of a square prism, one side of whose base measures 4 inches, and whose altitude is 6 inches. Entire surface = convex surfaces + areas of bases. 11. The convex surface of a square prism is 600 square feet, the altitude is 15 feet. What is the length of one side of the base ? 12. The entire surface of a square prism is 1650 square inches. One side of the base measures 15 inches. What is its convex surface ? What is its altitude ? Convex surface = entire surface — area of bases. • Surfaces. 349 SURFACES OF PYRAMIDS AND CONES. 450. A pyramid is a body whose convex surface is made up of triangles having a common vertex, the base of the pyramid being a polygon. Pyramids are either right or oblique; regular or irregular ; triangular, quadrangular, pentagonal, etc. In a right pyramid, each of the triangles that make up the convex surface is isosceles. When, in addition, the pyramid is a regular one, these triangles will be equal to each other. The altitude of any of these equal triangles constitutes the slant height of a right regular pyramid. The altitude of the prism is measured by a line drawn from the apex to the centre of the base. AG is the slant height of the square pyramid, Fig. 3. AF is its altitude. 451. The cone is a body having a single circular base, and a curved convex surface sloping to the apex. In the right cone, Fig. 4, HI is the )j slant height, and HK is the altitude. LO is the altitude of the oblique cone, Fig. 4. Fig> 5# Fig. 3. 452. Written Problems. 1. The convex surface of a square pyramid consists of how many equal triangles ? Find the convex surface when one side of its base measures 4 inches and its slant height (AX) 6 inches. 2. Draw the development. 35° Chapter Six. To find the convex surface of a pyramid (or cone) multiply the perimeter (circumference) of the base by one-half the slant height. 3. Find the entire surface of the above pyramid. Entire surface = convex surface + area of base. 4. Calculate the entire surface of a square pyramid whose slant height is 18 inches, the area of its base being 144 square inches. 5. Draw the developed convex surface of a cone, the diameter of whose base is 4 inches, and whose slant height is 6 inches. Calculate the convex surface. 6. How many square inches of paper would be required to cover the side and the base of a cone 6 inches in diameter at the base, and having a slant height of 10 inches ? 7. Calculate the slant height of a cone whose altitude is 12 inches, the diameter of its base being 10 inches. What is its convex surface ? Note. — The slant height is the hypotenuse of a right-angled triangle, the other sides measuring 12 in. and 5 in., respectively. 8. What is the convex surface of a cone, the diameter of whose base is 6 inches, and its slant height 10 inches ? Draw the development. 6 in. 9. A semicircular piece of paper 6 inches in diameter is folded into a hollow cone (without overlapping). What will be the diameter AB of the mouth of the cone (the base) ? What will be the slant height BC? Volumes. 351 VOLUMES OF PRISMS AND OF PYRAMIDS; OF CYLINDERS AND OF CONES. 453. Written Problems. Suggestion. — Have the pupils construct of cardboard a hollow square prism of convenient size, and a pyramid having base and alti- tude respectively equal to those of the prism. Let them use sand or water to ascertain how many times the contents of the pyramid must be taken to exactly fill the prism. Volume of prism or cylinder = area of base x altitude. Volume of pyramid or cone = area of base x \ altitude. 1. Find the volume of a square pyramid, the area of the base being 9 square feet and the altitude 6 feet. 1 cu. ft. x 9 x i of 6. 2. What is the volume of a square pyramid whose alti- tude is 12 inches, one side of the base being 10 inches ? 3. The base of a prism is a triangle whose sides measure 3, 4, and 5 inches respectively. Find the solidity, its alti- tude being 10 inches. 4. The base of a prism 19 feet high is a rectangle whose sides are 9 feet and 13 feet. How many cubic yards does it contain ? 5. Find the volume of a prism whose bases are equi- lateral triangles, each side being 4 feet, and the height of the prism being 12 feet. 6. How many cubic feet are 6 ft. there in a stone roller 6 feet long, 8 feet in circumference ? 7. Find the volume of a cone whose altitude is 18 meters, diame- ter of base 6 meters. 35* Chapter Six. SURFACE OF SPHERE. 454. A sphere is a body all points on whose surface are equally distant from the centre. The distance from the centre to the surface is called the Ffc— radius of the sphere. The di- ameter is a line running between two points on the surface and passing through the centre. CG } CK, CD, CF, and CJ are radii ; AD and FG are diameters. 455. If a sphere be cut through at any part, the cut sur- face will be a circle. When the cutting plane passes through the centre of the sphere, the circle is called a great circle; other circles are called small circles. FXGG is a great circle ; HYIB and JLEZ are small circles. A 456. Take a wooden hemisphere and drive a tack into the centre of its curved surface. Commencing at the tack, care- fully wind a waxed cord about the curved surface, in the way a boy winds a top. When this surface is exactly cov- ered, cut the cord. Wind the same cord around a tack driven into the plane surface of the base of the hemisphere, pressing it closely to the surface. When the latter is entirely covered, just one- half of the cord will be used. The Sphere. 353 As a hemisphere is made by passing the cutting plane through the centre of the sphere, its base is a great circle of the sphere. The above experiment shows that the surface of the hemi- sphere is equal to that of two great circles of the same sphere. 457. The surface of a sphere is equal to that of four great circles. Since the surface of a great circle of the sphere is R 2 x 3.1416, the surface of the sphere is 4 R 2 x 3.1416 = D 2 x 3.1416. To find the surface of a sphere, multiply the square of the diameter by S.lJf.16. 458. Written Problems. 1. Find the surface of a sphere whose radius is 1 inch. 2. The diameter of a sphere is 2 inches. Find its surface, 3. What is the surface of a sphere whose circumference is 6.2832 inches ? 4. At 10 cents a square foot, what will be the cost of gild- ing a sphere 12 inches in diameter ? 5. Find the ratio between the surface of a sphere 1 foot in diameter, and the convex surface of a cylinder 1 foot high, the diameter of the base 1 foot. 6. What is the ratio between the surface of a sphere 1 foot in diameter, and the entire surface of a cylinder 1 foot high, the diameter of the base 1 foot ? 7. Find the surface of a sphere whose circumference is 20 inches. 8. What is the ratio between the surfaces of two spheres whose diameters are 1 inch and 2 inches, respectively ? 9. Find the ratio between the surfaces of two spheres whose diameters are 2 feet and 13 feet, respectively. 354 Chapter Six. VOLUME OF SPHERE. 459. Cut up a sphere (a round potato, for instance) into a number of small pieces, passing the knife in each case through the centre of the sphere. Each piece is a solid, having for its base a portion of the sur- face of the sphere, and for its altitude the radius of the sphere. When the pieces become very numerous, the base of each may be considered a plane and the solid a pyramid. The volume of each pyramid is equal to the base x | altitude ; and the total volume of all, which is the volume of the sphere, is equal to the total surface of all the bases, which is the surface of the sphere, multiplied by | altitude, that is, | radius, or £ diameter. Surface of sphere = D 2 x 3.1416, therefore, volume of sphere = D 2 x 3.1416 x £ D = ^X 3.1416. To find the volume of a sphere, multiply one-sixth of the cube of the diameter by 8.1J/.16. 460. Written Problems. 1. Find the volume of a sphere whose radius is 3 inches. 1 cu. in x 36 x 3.1416. 2. If the diameter of a sphere is 3 inches, what is its volume ? The Sphere. 355 3. What is the ratio between the volumes of two spheres whose diameters are one foot and two feet, respectively ? 4. Find the ratio between the volume of a sphere 1 foot in diameter, and that of a cube whose side is 1 foot. 5. The radius of a sphere is 18 inches. What is the cir- cumference of a great circle ? The surface ? The volume ? 6. What is the weight of an iron cannon-ball 12 inches in diameter, considering the weight of a cubic foot of water as 1000 ounces, and considering iron 7.5 times as heavy as water ? 7. Find the ratio between the volume of a sphere 4 inches in diameter, and that of a cylinder 4 inches in altitude, diameter of base 4 inches. Note. — Indicate the volume of each, and cancel. 8. A man has a cubical block of hard wood, its side measuring one foot, which he wishes made into a sphere one foot in diameter. What decimal part of the block is cut away? The volume of the sphere is about what fraction of the volume of the cube ? MISCELLANEOUS. 461. Written Problems. 1. If a piece of cloth is 20 yards long and f yards broad, how broad is another piece of cloth 12 yards long that con- tains as many square yards as the former ? 2. An iron beam 16 feet long, 2\ feet broad, and 8 inches thick, weighs 1280 pounds. What is the length of a similar beam whose breadth is Z\ feet, thickness 7£ inches, and weight 2028 pounds ? 3. What will it cost to carpet a room 22^ feet long by 15| feet wide with carpet 2 \ feet wide, costing $1.50 per yard? 3S& Chapter Six. 4. What is the length of a box 6| feet wide and 1\ feet high, that will exactly contain 12 boxes 4£ feet long, 2>\ feet wide, and 2\ feet deep ? 5. What is the value, at $120 per acre, of a square field whose side is 35.25 chains? 10 square chains = 1 acre. 6. Find the capacity, in bushels, of a bin 22 feet long, 14 feet wide, 12 feet high ? 7. How many gallons will a tank hold, its dimensions being 4 ft. 1 in. by 3 ft. 8 in. by 2 ft. 3 in. ? 8. How many square yards are there in the walls and the ceiling of a room 21 feet long, 18 feet wide, 12 feet high? 9. A tank 5% feet by 6 feet by 7 feet can be emptied by two pipes, one of which discharges 9 gallons per minute and the other 7 gallons per minute. How long will it take each to empty the tank ? How long will it take both together ? 10. A parlor is 18 feet long, 15 feet wide. Make a dia- gram, showing how carpet 27 inches wide can be laid without cutting the carpet lengthwise. Which would be the better way to lay carpet 30 inches wide in the above room ? 11. Calculate the number of running yards of carpet 30 inches wide needed for the floor of the above room, including 4 i yards wasted in matching the pattern. Find the cost of carpeting the room at 95 cents per running yard for carpet, 5 cents per square yard for lining, and 10 cents per running yard for sewing and laying. 12. A room is 18 feet wide, 24 feet long, and 9 feet high. There are two doors 4 feet wide, 7-J- feet high ; two windows 4 feet wide, 6 feet high ; and a fireplace 5 feet square. How many square feet of plastering will there be on the walls Miscellaneous. 357 and ceiling, deducting for a baseboard 12 inches wide ? How many running feet of baseboard will be needed ? Draw "development" of the above room, showing the four walls and the ceiling, and locating the doors, the windows, and the baseboard. Do not use baseboard where it is not required. 13. At the rate of $1400 for a pile of lumber 25 feet long, 20 feet wide, 10 feet high, what is the value of a pile 50 feet long, 40 feet wide, 20 feet high ? 14. If it costs $ 14 to paint the walls and the ceiling of a room 25 feet long, 20 feet wide, and 10 feet high, what will it cost to paint the walls and the ceiling of a room 50 feet long, 40 feet wide, and 20 feet high ? 15. Measure accurately the interior dimensions of a quart or a pint cup, and calculate its volume. Note. — How many cubic inches in a quart, liquid measure ? 462. Circular Measure. 60 seconds (") 1 minute (*). 60 minutes 1 degree (°). 360 degrees 1 circle. 16. If the equatorial circumference of the earth is 25,000 miles, how many miles apart are two places on the equator, the distance between them being 20° ? 20° = J; circle. 17. What is the length of a degree on a circle whose diameter is 18 feet ? 18. The 60th parallel of latitude is a circle one-half as long as the equator. How many miles due east of Christi- ania is St. Petersburg, both situated on this parallel, the former being 10° east of Greenwich, and the latter 30° east? 358 Chapter Six. LONGITUDE AND SOLAR TIME. Note. — This topic should be taught in connection with the study of Mathematical Geography. The globe should be used to show the pupils that all places on the same meridian have the same solar time, that a difference in longitude of 15 degrees produces a difference in time of 1 hour, and that the more easterly of two places has the later time. 463. Preliminary Exercises. 1. The difference in time being 1 hour for each 15 degrees, find the difference in longitude between two cities differing in solar time 3 hours. 2. Two places differ in longitude 60 degrees. What is their difference in solar time ? 3. London is 75° east of Philadelphia. When it is 1 o'clock at Philadelphia, what is the time at London ? 4. When it is 2 p.m. at London, what is the time at Phila- delphia ? 5. How many degrees of longitude correspond to a difference of 3 hr., 40 min. in solar time? 6. What is the difference in longitude between Phila- delphia, 75° west longitude, and St. Petersburg, 30° east longitude ? 7. Washington is in 77° west longitude, and uses "stand- ard time," that is, the time of 75° west longitude. What is the difference between the correct time at Washington and its clock time ? 8. A town in 84° west longitude uses standard time, that of 90. What is the correct time when the clocks are striking 12, noon ? 9. Chicago is 87° 35' west of Greenwich. Is it earlier or later than noon at Chicago when it is noon at Greenwich ? Why? Standard Time. 359 STANDARD TIME. 464. In 1883, the railroads of the United States adopted a system of dividing the country into four time sections, each of 15° longitude. The 75th meridian west of Green- wich, which passes between New York and Philadelphia, was selected as the starting-point. The section governed by the time of this meridian, called eastern time, included the territory between the Atlantic coast and a line drawn through Detroit, Pittsburg, Wheeling, Parkersburg, Hunt- ington, Bristol, Tenn., Augusta, G-a., and Charleston, these cities being the termini of important railroads. Central time is governed by the time of the 90th meridian, and is used by the section west of Detroit, etc., to Bismarck, North Platte, Dodge City, etc. The next section which takes the time of the 105th meridian, called mountain time, extends to Helena, Ogden, and the western boundary of Arizona. The rest of the country to the Pacific Ocean takes the time of the 120th meridian, called Pacific time. 360 Chapter Six. SOLAR TIME. 465. Written Exercises. 1. Find the difference between the sun time of London and that of Chicago, longitude 87° 35' west of London. A difference of 15 degrees of longitude makes a difference of 1 hour ; of 16 minutes of longitude, a difference of 1 minute ; of 15 seconds of longitude, a difference of 1 second. If 1 degree of longitude made a time difference of 1 hour, the differ- ence in time between London and Chicago would be 87 hr. 35 min. ; as it takes 15 degrees to make a difference of an hour, the difference 15 )87 hr. 35 min. of time between London and Chicago 5 hr. 50 min. 20 sec. is ^ of 87 hr. 35 min. Dividing, there- fore, 87 hr. 35 min. by 15, we get the time difference as 5 hr. 50 min. 20 sec. To find the time difference, divide the longitude difference etopressed as hours, minutes, and seconds, by 15. t. When it is midnight at London, what is the sun time at Chicago ? Since the more easterly place has the later time, it is 5 hr. 50 min. 20 sec. before midnight at Chicago. 12 hr. (p.m.) — 5 hr. 50 min. 20 sec. = 6 hr. 9 min. 40 sec. p.m. Ans. 3. Two places differ in longitude 37° 18V What is their difference in solar time ? 4. Find the difference in longitude between two places differing in solar time 3 hr. 44 min. Multiply 3° 44' by 15. To find the longitude difference, multiply by IS the time difference expressed as degrees, minutes, and seconds. 5. Find the difference in sun time between two places in longitude 74° 31' and 93° 14' west of Greenwich, respec- tively. Solar Time. 361 6. When it is noon at a place 11° east of Greenwich, it is 1 : 30 p.m. at another place. Find the longitude of the latter place. Note. — Owing to the general use of standard time by civilized countries, problems in longitude and time have no practical value except for navigators. The following problems should be worked only after more important topics have been completed. Note. — The word "time" in the following problems means "mean solar time." 7. Given the longitude of A as 95° east, and that of B as 74° east, and the time at A as 1:30 p.m., to find the time at B. Since the latitude of B has no bearing upon its time, both places may be located upon the same line running east and west. Time difference = ? hours. Time=? Time 1:30 p.m. B A West 1 1 1 East 0° 74° 95° Longitude difference = 21°. Locate the prime meridian (that of 0°), then the meridians of 74° and 95° east. Mark above the last two the names of the places, B and A. Write above A its given time, 1 : 30 p.m. To find the time at B, we must find the difference of time between B and A. The difference in longitude is 95° - 74° = 21°. The dif- ference in time is 21 hours -f- 15. Note. — Remember that the more easterly of the two places has the later time. 8. A is situated in 71° west longitude, B in 107° west longitude. What time is it at B, when it is noon at A ? Time difference = ? Time ? 12 m. B A West 1 1 1 East 107° 71° 0° Longitude difference = ? 362 Chapter Six. 9. Find the longitude of B, whose time is 8 : 10 : 30 a.m., when it is 7 : 15 a.m. at A, whose longitude is 156° 48' west. Time difference = ? 7:15 a.m. 8:10:30 a.m. A B West 1 1 1 East 156° 48' Longitude = ? 0° Longitude difference = ? Since B has the later time, its location is east of A. The difference in time, being nearly an hour, shows the difference in longitude to be nearly 15°. Find the exact difference. Is it to be added to 166° 48' or subtracted from it, to give the longitude of B ? 10. When it is 2:40 a.m. at A, in 57° 24' west longitude, it is 10 a.m. at B. Find the longitude of B. Time difference = 7\ hours. 2:40 a.m. 10 a.m. A B West 1 1 1 East 57° 24' 0° Longitude = ? Longitude difference = 15° x7| = 110°. If we go 110° eastward from A, we shall reach the prime meridian after going how many degrees and minutes ? How many more degrees and minutes must we travel to reach B? Is B in east or in west longitude ? 11. When it is noon at B, what is the time at A, the former being in longitude 44° east, and the latter in longi- tude 57° west ? Time difference = ? Time = ? 12 m. A B West 1 1 1 East 67° 0° 44° Longitude difference = 101°. Why ? Solar Time. Find the longitude or the time : 363 Longitude of A. 12. 63° east Time at A. 9 A.M. 13. 57° 25' east ? 14. 156° 48' west 3:15 p.m. 15. ? 16. 2° 15' west 17. 27° 10' east 18. ? 19. 74° 56' west 20. 4' 30" east 21. ? 11:42 a.m. 6:53 a.m. 9 4:10 p.m. 3:50 a.m. 8:47 a.m. 10:30 p.m. Longitude of B. 54° east 83° 20' east ? 56° 25' west 67°: 48' east 27° 10' west 18° 4' east 9 90° 15' west 32° 30' east Time at B. 9 1 : 45 p.m. 4:10 p.m. 1:27 p.m. 9 12 m. 11:30 a.m. 11 A.M. 9 6:48 p.m. REVIEW. 466. Oral Problems. 1. At what per cent will $12, in 3 yr. 4 mo., amount to $14? 2. What will be the cost of a building lot 100 feet long and 50 feet wide at 50 ^ a square foot ? 3. A horse was sold for $90, at which price 12^% was gained. What per cent would have been gained by selling him for $100? 4. What is the premium for insuring $6000 on my house at 1\% ? 5. How many cubic inches in a ten-inch cube ? 6. Bought 2 chairs at $1.25, one wash-tub for $1.50, 1 table for $3.00, and 5 dozen glasses at 48^ a dozen. Gave a ten-dollar bill in payment. How much change did I receive ? 364 Chapter Six. 7. My desk is 1£ feet long, and 1 foot wide. How many inches around it ? 8. If a man spends 50^ a day during April, May, and June, what does he spend in the three months ? 9. A grocer bought 15 barrels of flour at $5 a barrel. At what price must he sell them to gain $ 36 ? 10. Seven-eighths of James's vacation will be equal to seven-ninths of yours ; yours will be 63 days. How many will his be ? 11. A man sold two cows for $30 each. On one he gained 25% ; on the other he lost 25 %. Did he gain or lose, and how much ? 12. What principal, in three years and 4 months, at 6%, will give $40 interest? Note. — To the following ten problems the wrong answers are very frequently given. 13. Sold a horse for $ 250, losing $ 50. What is the loss per cent ? 14. If 3 boys solve 3 problems in 3 minutes, how long will it take 6 boys to solve 6 problems ? 15. Two boys go fishing; one brings 7 cakes for lunch, the other brings 5 cakes. A third boy joins them at noon, and pays 12^ for his share of the meal. How should the first two divide the money received ? 16. If 100 per cent is gained by selling an article for $ 1, how much would be gained by selling it for $ 2 ? 17. A boy had a slate 5 inches by 7 inches. He buys one twice as large. Give the dimensions of the new slate. 18. A man wishes to put up on the front of his lot a fence 30 feet long. If the posts are 6 feet apart, how much will they cost at 25^ each? Review. 365 19. One-half the money taken in by a newsboy is profit. What per cent does he make ? 20. 50 per cent of a number multiplied by 30 per cent of the same number equals 60. What is the number ? 21. Three-fourths per cent of a number is 90. What is the number ? 22. An importer receives some cases of goods numbered consecutively. How many cases are there, if the number of the first is 28, and of the last 75 ? 467. Written Problems. 1. What is the profit on 9 boxes of oranges, each con- taining 20 dozen, bought at $ 1.10 per hundred and sold at the rate of 18 for 25^? 2. How long will it take a train to go 176 miles at the rate of 3520 feet per minute ? i 3. If .0375 of an acre of land is worth $ 9, what is -^ acre worth ? 4. At £ 1 Is. Id. per barrel, how many barrels of flour can be bought for £ 161 17s. 6d. ? 5. If 580 tiles, each 6 inches square, will cover a certain area, how many tiles, each 4 inches long and 3 inches wide, will be needed to cover the same area ? 6. A man receives $ 1500 commission on his yearly sales. What is the amount of his sales if he is allowed \ per cent commission ? 7. At what rate per cent will $360 produce $3.06 in- terest in 2 mo. 12 da. ? 8. Find the square root of 25.00400016. 9. What will be the capacity, in gallons, of a tank 9 ft long, 6 ft. 8 in. wide, and 6 ft. 5 in. deep ? 366 Chapter Six. 10. What decimal multiplied by 312.5 will give the sum of I, ^ t> -09375, and 2.46 ? 11. A dealer bought a lot of coal $ 4.95 per ton. What was the total cost if he gained $ 142.50 by selling it at $ 5.25 per ton ? 12. Find the value of ?i±iA_ 1 f 64. 1| x 3 ¥ T 13. The front wheel of a wagon measures 13 feet in cir- cumference. What is the distance travelled in miles, rods, yards, etc., when the wheel has made 527 revolutions ? 14. Write in words .349, 300.049, $h% 300^^. 15. If a bar of silver weighing 4 lb. 6 oz. 12 pwt. is worth £6 14s. 2d., what is the value (in English money) of a similar bar weighing 7 lb. 9 oz. 12 pwt. ? 16. A and B form a partnership. A furnishes $5000; B, $ 10,000. During the year A draws $ 1500 of the profits and B draws $1000. At the end of the year the entire business is disposed of for $ 20,000. What amount should each receive ? 17. What per cent is gained on an article bought for 20 per cent less than its value and sold for 20 per cent more than its value ? 18. A person loans $ 750 to M and $ 1200 to N at the same rate. From the latter he receives half-yearly $ 9 more interest than from the former. What is the annual rate of interest ? 19. A 4-months note for $ 375, drawn March 19, was dis- counted at a bank June 4. Find the proceeds. Eate, 6%. 20. M can do a piece of work in 4 days, N can do it in 5 days, O in 6 days. How long will it take the three to- gether to do the work ? 1 day + (£ + | + $). Analyze. Stocks. 367 STOCKS. 468. Some undertakings, such as the construction of a railroad, the building and equipment of a factory, the de- velopment of a mine, and the like, require more money than any individual may care to risk. It then becomes necessary to secure the cooperation of a number of persons. The people of a certain town desire to build a street rail- road, the construction and equipment of which will require $50,000. The projectors organize a company. If it is desired to interest people of small means, the required capi- tal may be divided into shares of $10 each, making the total number of shares 5000. If the shares are fixed at $100 each, there will be 500 shares. To every purchaser of shares, a certificate is issued, coun- tersigned by the officers of the company, setting forth the amount of capital, the total number of shares, and the num- ber issued to the holder of the certificate. At certain fixed periods, quarterly, semi-annually, or an- nually, the directors of the company determine what part of the profits shall be distributed to the stockholders, the remainder being reserved for new cars, extension of the road, etc. The profits thus distributed are called dividends. 469. Written Problems. 1. A company is organized with a capital of $50,000, divided into shares of $ 100 each. What part of the stock is held by the owner of 10 shares ? 2. If dividends of $2000 are distributed at the end of six months, how much should the holder of 10 shares receive ? 3. The company announces the dividend as a certain per cent of the capital. What per cent dividend is declared in this case ? To what per cent per year is it equal ? 368 Chapter Six. 4. Mr. H. has $4500 in the savings bank, on which he receives 4 per cent interest. He gives this amount for 30 shares of the stock. What price does he pay per share? What per cent of the par value ? 5. If the next semi-annual dividend is 4%, how much more income does Mr. H. receive from the stock than he would obtain from the savings bank ? 6. What per cent has Mr. H. received for six months on his investment of $4500 ? 7. If Mr. H. sells the 30 shares at $164.50 per share, how much more does he receive for it than it cost him ? 470. Stocks are generally bought and sold by brokers, who charge, as a rule, J% of the par value for buying or for selling. The prices of the stocks as given in the news- papers are generally a percentage of the par value. Thus, the New York quotation of Pennsylvania E..R. on March 4, 1903, is 151-J-. This means that the shares of the Penn- sylvania R.R. sold for $50x1.51^, or $75.75, the par value being $50. The Philadelphia papers of the same date, however, quote the stock at 75f , it being the practice in that city to give the price per share. 471. "Written Exercises. 1. Find the cost of 240 shares Anaconda Copper Mining Co., par value $25, at 134|, brokerage \%. Cost = $25 x 240 x (1.34$ + .00J). To find the cost, multiply the face value of the given number of shares by the rate plus the brokerage. 2. How much brokerage is paid by the buyer of 275 shares bank stock, par value $100, brokerage £%? | % of $100 x276. Stocks. 369 3. Paid $11,445 for 120 shares Cleveland, Cincinnati, Chicago, & St. Louis, par value $100, brokerage £%. What was the value of the stock per share ? The brokerage on 120 shares, par value $ 100, is £% of $ 12,000, or $15. The cost of the stock is, therefore, $11,430. Dividing by the number of shares gives the value per share. ($ 11,445 - } % of [$ 100 x 120]) -s- 120. 4. Bought 150 shares Evansville and Terre Haute at 69f, brokerage \%, paying for it $5212.50. What is the par value per share ? The cost of each share is $ 5212.50 -*- 150. Divide this cost by the rate, including the brokerage, .69| + .00$. ($ 5212.50 -r- 150) + (.69f + .00$). 5. A broker sells for a customer 200 shares stock, par value $25, at 102 J. If he retains -$% brokerage, how much does he pay over to the former owner of the stock ? 6. A man buys 60 shares bank stock, par value $ 100, at 450, no brokerage. If the annual dividend is 18%, what is his income therefrom ? What per cent does he receive on his investment ? Note. — Dividends are based upon the par value. 7. A manufacturing corporation makes $20,000 a year over all expenses. The stock consists of 4000 shares, par value $ 50. What rate of dividend can be declared ? What per cent on his investment does a man receive who has bought his stock at 175, no brokerage ? 8. A capitalist bought 360 shares stock, par value $ 25, at 168£. He paid therefor, including brokerage, $ 15,176.25. What was the rate of brokerage ? 9. A broker sold 250 shares, par value $100, at 107f. He deducted brokerage and paid over the proceeds, amount- ing to $ 26,875. Find the amount of the brokerage and the rate per cent. 370 Chapter Six. 10. A woman invests $ 35,050 in stock at 175, brokerage J%. If the annual dividends are 7^-%, what is her income from the investment ? 11. Which investment will pay better, one in a gas com- pany paying 6% dividends annually, their stock selling at 150, the other in a bank paying 7% dividends annually, stock selling at 175 ? 12. What annual dividend should be declared on railroad stock bought at 125, so that the buyer will receive 4% per annum on his investment ? What semi-annual dividend ? 13. What will be the cost of 17 shares of canal stock, par value $ 50, at 93 J, and 143 shares gas stock, par value $ 10, atl02f? Note. — An examination of the prices of stocks as given in the newspapers will show that the rate of dividends constitutes but one consideration influencing buyers. The following prices were offered March 4, 1903, f cr stocks of four banks, respectively, each of which paid 6 per cent dividends annually ; 185, 245, 390, 685. Purchasers of shares of the last three banks evidently hoped for larger dividends in the immediate future. . The values of bonds depend in the first instance upon the character of the corporation issuing them, then upon the rate of interest and the length of time before redemption. United States bonds bring the highest prices, as buyers have no fear of the failure of the government to keep its promises. The following are the prices obtained at the last sales reported to March, 1903 : Date of Rate. Redemption. Price Paid. Last Sale. U. S. 2's 1930 108f Nov. 14, 1902 U. S. 4's 1907 no* Feb. 4, 1903 U. S. 4's 1925 136 Feb. 26, 1903 U. S. 5's 1904 103 Feb. 23, 1903 The 5 per cent bonds, although bearing the highest rate of interest, bring only 103, as they will be redeemed at par a little more than a year after they are bought. The purchaser, who paid $ 103 for a bond, will receive for it in 1904 only $100, with about $5 interest, his net profit for the year being $2 on an investment of $ 103. Bonds. 371 BONDS. 472. A bond is a form of interest-bearing note issued by a corporation. A coupon bond is one containing certificates of interest which are cut off and presented for payment as interest becomes due. A 10 years' U. S. coupon bond has 40 cou- pons, one for each quarter-year's interest. Upon each is engraved the date when due, and the sum payable, which is $ 10 in the case of a $ 1000 f our-per-cent bond. A registered bond contains no coupons, a check for the interest being mailed to the owner, whose name is registered on the books of the corporation. 473. Written Exercises. 1. A railroad company needing more money to extend its road, issues bonds bearing interest at 4%. If these bonds are sold at 95, what rate of interest on the money invested does the owner of a bond receive ? For each $95 invested the owner receives $4 interest. The rate is 4 -4- .95. To find the rate on the investment, divide the rate of interest by the rate paid for the bond, including brokerage, if any. 2. Find the cost of 20 one thousand dollar bonds at 120£, brokerage §-%. 3. If the foregoing bonds bear interest at the rate of 6%, what is the annual income ? What rate per cent annually is received on the sum invested ? 4. A man desires to secure an annual income of $ 650 for his daughter. What is the face value of 5% bonds necessary to produce this income? What will be the cost of 5% bonds of Denver & Rio Grande at 107, brokerage l%? 372 Chapter Six. 5. A person desirous of obtaining a semi-annual income of $900 is offered Central Pacific 4's at 99 J, Chicago & Alton 3's at 83 J, or Western Union 4£'s at 104 J, no brokerage in any case. Find the difference between the smallest and the largest outlay necessary to secure the desired income from these bonds. Note. — 4's means bonds paying 4 per cent interest per year. 6. How much money must be invested in the U. S. 2's to yield a quarterly income of $225, bonds selling at 108|, brokerage \°/ ? 7. An owner of 6 per cent bonds sells them at the market quotation of 118, and invests the proceeds in 4£ per cent bonds. The latter investment yields him the same income as the former. What did he pay per hundred for the 4^- per cent bonds, no brokerage ? 8. A, having a farm of 109 acres, which rents for $ 681.25 above taxes, etc., sells the same for $200 per acre, and invests the proceeds in U. S. 2's @ 108£%, brokerage |%. Will his yearly income be increased or diminished, and how much? 9. What is the difference in the rate of income obtained from an investment in U. S. 2's at 109|, and one in U. S. 4's at 137f, brokerage \% in each case? Note. — In calculating the rate of interest in the foregoing exam- ples, the time of the redemption of the bonds is omitted from consid- eration. In the following example, however, the term of the bond is made an element in the computation. The holder of it has received $30 in interest, and he is paid $100 for the bond. Ignoring the mat- ter of compound interest, the question becomes: At what rate will $ 104 amount in 6 years to $ 130 ? * 10. Mr. Tower pays $104 for a $100 five per cent bond. At the end of six years the bond is redeemed at par. What rate of interest does he receive on his investment of $ 104 ? Exchange. 373 DOMESTIC EXCHANGE. 474. Arthur S. Somers, of Memphis, Tenn., wishes to pay- John R. Thompson, of The City of New York, $ 3475.86. If Mr. Somers sends a check, drawn on his Memphis bank, Mr. Thompson will be charged a certain sum by his New York bank for collecting the amount of the check, and he will thus receive somewhat less than the sum due him. Mr. Somers, therefore, buys from J. E. Washington, a Memphis banker, who has funds in a New York bank, the following SIGHT DRAFT. f 3475 J£6^. Memphis, Tenn., Aug. 9, 1904. At sight, pay to the order of John R. Thompson Three Thousand Four Hundred Seventy-five -fa Dollars, value received, and charge to the account of To Chemical Bank, JOSEPH E. WASHINGTON. The City of New York. Mr. Somers is charged for this draft a premium of $ 1.50 per $ 1000; that is, he pays Mr. Washington $1001.50 for each $ 1000. The cost of the draft is, therefore, $ 3475.86 X 1.0015, or $ 3481.07. 475. Exchange is at a premium when the cost of a sight draft is greater than its face; it is at a discount when the cost of a sight draft is less than its face. 476. Mr. Thompson could collect the sum due him by making a draft on Mr. Somers as follows : TIME DRAFT. $ 3475_8 T 6 r . New York, Aug. 9, 1904. At three days' sight pay to the order of The National Bank of Commerce Three Thousand Four Hundred Seventy- five and ■££$ dollars, value received, and charge to the account of JoHN R# Thompson. To Arthur S. Somers, Memphis, Tenn. 374 Chapter Six. Mr. Thompson deposits the draft in the National Bank of Commerce for collection. This bank forwards it to a Mem- phis bank. The latter notifies Mr. Somers. If he wishes to pay the draft at the expiration of three days, he writes across the face in red ink, "Accepted," with the date, " Aug. 11, 1904/' and adds his signature. Aug. 14 he pays the money to the Memphis bank, which notifies the Bank of Commerce, and the sum is placed to the credit of Mr. Thompson, less the cost of collection. 477. A sight draft is payable upon presentation, except in those states allowing " days of grace." A time draft is one payable a specified number of days after acceptance. In some states three additional " days of grace " are allowed. 478. Written Exercises. 1. Find the cost of a Boston draft on New York for $ 1875, at 12 ^ discount per $ 1000. Face $ 1875. Discount $ 1875 x .00012 .225 $1874.775 Ans. $ 1874.78. To find the cost of a sight draft, add the premium to the face, or subtract the discount from the face. 2. What will a St. Louis merchant pay for a draft on New York for $ 2460.53, at 50 ^ premium per $ 1000 ? 3. At \°lo premium, find the cost of a sight draft for $1843.60. 4. At 75^ discount per $1000, how much will cost a sight draft on Milwaukee for $946.75? 5. Paid $ 632.18 for a sight draft on Milwaukee. What was the face of the draft, the discount being ■&%? Exchange. 375 BILLS OF EXCHANGE. 479. Bills of exchange are either domestic or foreign. A domestic bill of exchange is called a draft, the term bill of exchange being generally applied only to foreign bills. 480. Fred Johnston owes John Ahern & Co., of London, £ 180 17s. 6d. He buys from John Cottier & Brother a bill of exchange drawn on their London correspondent. The bill is drawn in duplicate, one being sent by Mr. Johnston to John Ahern & Co., and the other being retained by the former to send in case of the loss of the first. When either is paid the other becomes of no value. The following is the form of the first of a set of exchange. Exchange for £ 180 17s. 6d. New York, Dec. 14, 1903. Sixty days after sight of this First of Exchange (Second unpaid), pay to the order of John Ahern & Co., One Hun- dred Eighty Pounds Sterling, Seventeen Shillings Six Pence, value received, and charge the same to account of To James Lennon & Co., John Cottier & Brother. London. No. 39. Upon receipt of this bill, John Ahern & Co. present it for acceptance. They receive the money sixty days there- after. 481. Written Exercises. 1. Find the cost of the above bill at $4.87 per pound. £200 = $974.00 20 = 97.40 £ 180 = $ 10s. = 2.435 ££ 5s. = 2s. 6d. = 376 Chapter Six. 2. What is the cost of a cable transfer of £251 lis. 9&, at $4.88£ per pound? £250 = ^1221.25 \ of £1000 1 = 10s. = Is. = 6d.= 3d. = The newspapers give quotations of foreign exchange for sight and 60-day bills, also for cable transfers. 482. The New York quotations for French exchange give the number of francs for $1. Paris cable transfers 5. 16 \ @ 5.15f. Paris bankers' 60 days 5.18f@5.18|. Paris bankers' sight 5.16| @ 5. 16 J. The quotations for German exchange give the value in U. S. money of 4 Reichmarks (or marks). Reichmarks (4) 60 days 95J @ 95J. Reichmarks (4) sight 95| @ 95$. 3. Find the cost of a sight bill on Paris for 1000 francs, at 5.16J francs for $ 1. 4. Find the cost of a 60-day bill of exchange on Berlin for 1874.35 marks, at 95J fi for 4 marks. 5. What will be the face in marks of a sight bill of ex- change on Berlin that can be bought for $ 1000, at 95 J ^ for 4 marks ? 6. A New York merchant pays $ 1637.50 for a 60-day bill on Paris. What is the face of the bill, the rate of ex- change being 5.18J francs for $ 1 ? Exchange. 377 7. At $4.88 per pound, what will be the face of the sight bill on London that can be bought for $ 1500 ? 18750 * £307 7s., etc. g|| = 18750 61 )18750 i& 61 _450 to £23 remainder 20_ 460s., new dividend 8. Bought goods in London amounting to £ 437 5s. 10c?. less 4%. How much do I pay in Boston for a sight bill of exchange at $ 4.88^ to settle the account ? 9. What will be the cost in Chicago for a 60-day bill on Paris that will pay for the following articles ? Rate, 1 franc -10} A 18 pieces silk, 44 meters each, at 25 francs per meter, less 1\% 3 pieces of cloth, 50 meters each, at 20 francs per meter, less 5%. Packing charges, 60.50 francs. 10. I wish to send a sight bill of exchange on Berlin in payment of the following invoice : 4 cases musical instruments, amounting to 3598.60 marks, less 10, 5, and 2\%. Freight to Hamburg, 165 kilos, at 4.80 marks per kilo. At 95J ^ for 4 marks, what will be the cost of the bill of exchange ? 11. If the rate of exchange is 50^ discount per $1000, what is the face of the sight draft on Boston, that can be bought in New York for $ 1000 ? Note. — $ 999.50 in New York will buy a sight draft on Boston for $1000. 12. When the premium is $1.25 per $1000, Mr. Brown pays $ 1634.04 for a draft on Louisville. What is the face of the draft? 378 Chapter Six. COMPOUND INTEREST. 483. Compound Interest is interest on the principal and on the unpaid interest, which is added to the principal at regu- lar intervals. The interest may be compounded annually, semi-annually, or quarterly, according to agreement. Compound interest is allowed by savings banks. It is not collectible on notes, mortgages, or the like. 484. "Written Exercises. 1. Find the amount of $375, for 1 year, at 6%. Con- sidering this as a new principal, find the amount for a year, same rate. Find the amount of this last principal for 3 months. 2. What is the amount of $ 375, for 2 yr. 3 mo., at 6%, compound interest ? 3. What is the amount of $ 375, for 2 yr. 3 mo., at 6%, the interest compounded semi-annually ? Principal, $375. 3% 11.25 6 months' interest 386.25 Amount 6 months. 3% 11.5875 6 months' interest. Amount 1 year, 3% 6 months' interest. Amount 1£ years, etc., etc., etc. 4. Find the compound interest on $ 375, for 2 yr. 3 mo., at 6 per cent, compounded semi-annually. Note. — To find the compound interest, deduct $ 375 from the amount for 2 yr. 3 mo. 5. What is the amount of $ 100, at compound interest, for 3 years, interest at 6%, compounded annually ? Annual Interest. 379 ANNUAL INTEREST. When the maker of a note fails to keep his contract to pay interest annually, the laws of some states, including Michigan, permit the col- lection of simple interest on the deferred payments of interest. 485. Written Problems. 1. Find the amount due June 1, 1908, on the following note, no payments of principal or interest having been Detroit, Mich., June 1, 1904. Tour years after date, without days of grace, I promise to pay to the order of Daniel W. Lawler, Six Hundred Dollars, value received, with annual interest at six per cent. $600^. George Oxj^ard. Principal, $600.00 Interest, 4 years, at 6 %, 144.00 3 years' interest, at 6 %, on the 1st year's interest, $ 36, 6.48 2 years' interest, at 6 %, on the 2d year's interest, $ 36, 1 year's interest, at 6 %, on the 3d year's interest, $ 36, Amount due June 1, 1910, $ Find the interest on the principal for the entire time, and on each annual interest for the time it remained unpaid. The sum of the principal and all the interest is the amount due. 2. Find the amount due, at 5%, for 5 years, on a note for $ 1200, annual interest being unpaid. 3. The maker of a note for $ 900, with annual interest at 7%, makes the first and the second interest payments when due. How much will he owe at settlement, 6 years after the date of the note ? 4. Find the difference between the amount due at 6% for 3 years on a note for $ 300, annual interest unpaid, and the amount of the same sum placed at compound interest for the same time at the same rate. 380 Chapter Six. 5. What is the amount of a note for $ 720, at 4 years, at 4|%, annual interest unpaid after the first year? 6. Find the amount due March 1, 1906, on a note for $500, dated March 1, 1900, with interest at 6%, annual interest unpaid after the third year. METRIC SYSTEM. 486. The metric system, which is used in nearly all the countries of continental Europe, is based upon the meter. The length of the meter is one ten-millionth part of the length of the meridian from the equator to the poles — about 39.37 inches. The subdivisions of the meter are denoted by the Latin prefixes milli (tuW)» centi (y-J-^), deci (y 1 ^). For the multi- ples, the Greek prefixes deka (10), hecto (100), kilo (1000), and myria (10,000) are used. 487. It will be noticed, in the table below, that small letters are used for the abbreviations of the Latin prefixes of the subdivisions, and capital letters for the Greek pre- fixes of the multiples. The following is the table of 488. Measures of Length. 10 millimeters (mm) 1 centimeter (cm) 10 centimeters 1 decimeter (dm) 10 decimeters 1 meter (m) 10 meters 1 dekameter (Dm) 10 dekameters 1 hectometer (Hm) 10 hectometers 1 kilometer (Km) 10 kilometers * 1 myriameter (Mm) The units of this table in common use are the centimeter, the meter, and the kilometer. Long distances are expressed in kilometers. The thickness of wire is given in millimeters. Metric System. 381 489. Written Problems. 1. What will be the cost in francs of 380 m 75 of dress goods at 2 f 60 per meter ? 380 m 75 is read 380 meters 75 centimeters. It is also written 380.75 m, but the first method is the more common one in Europe. 2 f 60 is read 2 francs 60 centimes. A period (.) is not used after the abbreviations of meter, liter, franc, etc. 2. How many square meters in a piece of carpet 26 m 50 long, 85 cm wide ? 3. How many square meters in a circle whose diameter is 15 meters ? 4. An are is a surface 10 meters long, 10 meters wide. How many ares in a field 135 meters long, 69 meters wide ? 5. Find the area in ares of a right-angled triangle whose base is 245 meters, hypotenuse 875 meters. 6. A stere is a cubic meter. What will be the cost, at 8 f 50 per stere, of a pile of wood 10 meters long, 1 meter wide, 3.25 meters high ? 7. A cube one decimeter each way contains a liter (1), which is the principal unit of dry and liquid measure. How many liters' capacity has a tank 10 m 50 long, 8 m wide, 6 m 50 high ? Change each dimension to decimeters. 8. How many bottles, each containing 1 75, can be filled from a hogshead containing 222 1 ? 9. How much will be received for 36 bags of beans, each containing 68 liters, at 1 mark 25 per dekaliter ? 10. A liter of water weighs a kilogram (1000 grams). How many kilos of oil would a tank contain, its dimensions being 5 meters by 4 meters by 3 meters, the weight of the oil being 92% of the weight of water? 11. Assuming the length of the meter as 39.37 inches, what is the length of the kilometer in yards ? 382 Chapter Six. . 490. Measures of Surface. 100 sq. mm = 1 sq. cm 100 sq. cm = 1 sq. dm 100 sq. dm = 1 sq. m = 1.196 sq. yd. 491. The square meter is the principal unit of surfaces, such as walls, ceilings, floors, etc. 100 centiares (ca) = 1 are (a) = 119.6 sq. yd. 100 ares = 1 hectare (Ha) = 2.47 acres. The are is the principal unit of surface of small plots of land. The area of a farm is expressed in hectares, of a country in square kilometers. 492. Measures of Volume. 1000 cu. mm = 1 cu. cm 1000 cu. cm = 1 cu. dm 1000 cu. dm = 1 cu. m = 35.316 cu. ft. The principal unit is the cubic meter. 493. The stere (cubic meter) is used for measuring wood. 10 decisteres (dst) = 1 stere (st) = 35.316 cu. ft. 10 steres = 1 dekastere (Dst). The stere is the only unit used. 494. Dry and Liquid Measures. 10 milliliters = 1 centiliter. 10 centiliters = 1 deciliter. Dry. Liquid. 10 deciliters = 1 liter (1) = .908 qt. = 1.057 qt. 10 liters = 1 dekaliter = 1.135 pk. = 2.642 gal. 10 dekaliters = 1 hectoliter = 2.837 bu. = 26.417 gal. 10 hectoliters = 1 kiloliter. 10 kiloliters = 1 myrialiter. The liter and the hectoliter are the principal units. Review. 383 495. Table of Weight. 10 milligrams (mg) = 1 centigram. 10 centigrams = 1 decigram. 10 decigrams = 1 gram (gr). 10 grams = 1 dekagram. 10 dekagrams = 1 hectogram. 10 hectograms = 1 kilogram (kilo) = 2.2046 lb. 10 kilograms (Kg.) = 1 myriagram. 10 myriagrams = 1 quintal. 10 quintals = 1 tonneau (ton). The kilo is the ordinary unit. Heavy articles are sold by the tonneau. 496. Written Exercises. 1. The Eiffel tower is 300 meters high. What is its height in feet? 2. The Danube is 2600 kilometers long. Find its length in miles. 3. A bottle filled with water weighs 1.170 kilos; the weight of the bottle is 420 grams. What is the capacity of the bottle in liters? 4. Find the weight in kilos of 15 liters of olive oil, which weighs .915 time as much as water. 5. A rectangular field 123 meters long, and 85.5 meters wide, yielded 13.25 hectoliters of wheat per hectare. The wheat weighed 84.350 kilos per hectoliter and sold for 23.50 francs per 100 kilos. What sum did the crop bring ? 6. What will be the cost in francs of papering a room 5 m 42 long, 4 m 18 wide, and 3 m 10 high, at 1 f 20 per square meter ? 7. Calculate the expense of building a wall 14 m 50 long, 7 m 80 high, m 22 thick, of bricks m 22 long, m 11 wide, m 06 thick, the bricks costing 58 francs per thou- sand and the labor, etc., 32 f 80 per cubic meter. 384 Chapter Six. 8. Find the profit on a pile of wood 20 meters long, 4 meters wide, 8 meters high, bought at 12 francs per stere, and sold at 4 francs per 100 kilos, the weight of the wood being .42 times the weight of water. 9. A liter of wheat weighs 760 grams. When ground it produces 89 per cent flour and 11 per cent bran. Find the weight of the flour that can be made from the wheat con- tained in a bin 2 m 60 long, 2 m 40 wide, and 1 m 50 deep. Find the value of the wheat at 4 f 85 per double dekaliter. 10. If sea water contains -£$ of its weight of salt, how many hectoliters of sea water should be evaporated to obtain 100 kilos of salt, a liter of sea water weighing 1.026 kilos ? REVIEW. 497. Oral Problems. 1. If I yard costs $4.50, what will £• yard cost? 2. If 3 men can do a piece of work in 4 days, how long will it take 24 men to do it ? 3. What principal at interest for 5 years, at 6 per cent, will produce $ 12, simple interest ? 4. A stack of hay will keep a cow 20 weeks, or a horse 15 weeks. How long will it keep them both ? Note. — What part will each eat in a week ? What part will both eat in a week ? 5. How many days from May 16 to July 5 ? 6. Sold a cow for $24, losing thereby 40% of the cost price. Had I sold her for 33^% advance on the cost, what should I have received for her ? 7. What will 460 pounds of tea cost at $ .48 per pound ? 8. If 12 ounces of bread are destroyed in making a gill of whiskey, how much will be destroyed in making a gallon ? 4 gills = 1 pint Review. 385 9. If the weight of air is 15 pounds on the square inch, what is it on the square foot ? 10. Seven is three-fifths of what number ? 11. What is the value of 960 pounds of wheat at $1.05 per bushel of 60 pounds ? 12. At what rate per cent will $400 make $37.50, simple interest, in 1 yr. 3 mo. ? 13. What is the brokerage on $10,400, at If % ? 14. What will 3280 feet of lumber cost @$25 per thousand? 15. A and B are partners; A puts in -^ of the stock, and B the remainder ; B's gain is $ 1400. Find A's gain. 16. What is the difference in the longitude of two places whose difference in sun time is two hours and three minutes? 17. A room is f as wide as it is long. Its length is 20 feet. How many square feet are there in the floor ? 18. If 5 yards of cloth cost 90^, what will f of a yard cost? 19. An agent insured a house for me at a commission of \°/ . His commission was $15. For how much was the house insured ? 20. A gold-digger who had 3 pounds of gold dust, lost 9 ounces. What per cent was left ? 498. "Written Problems. 1. What number must be added to the sum of -|, -J, and \\ to make 5^? 2. Find the interest on $ 2320, for 5 months and 21 days, at the rate of 7 per cent a year. 3. Find the interest on $640, from Sept. 3, 1904, to Oct. 30, 1905, at 6 per cent per annum. 386 Chapter Six. 4. At compound interest, what will $ 200 amount to in 1 year and 3 months, at 6 per cent, interest compounded semi-annually ? 5. A man drew out of the bank f of his money, and ex- pended 30% of 50% of this for 936 bushels of wheat at $ 0.87J a bushel. What sum had he left in bank ? 6. A house that cost $ 14,500 rents for $ 1189. What per cent does it pay on the investment ? 7. If 4 men dig a ditch 24 rods long in 20 days, how long a ditch can 5 men dig in 8 days ? 8. For what sum must a 60-day note be written to yield $ 294.75 at a bank, discounting at 6% ? 9. An agent receives $ 5616 for silk he has purchased and his commission on it at 4%. How many yards did he purchase at $ 1.50 per yard ? 10. What will be the proceeds of a 60-day note for $ 500, dated June 4, 1904, and discounted at a bank July 1, 1904, at 6% ? 11. At what rate will $142 gain $21.30 interest in 3 years ? 12. What is the duty, at 50^ a pound and 30% ad valorem, on 700 yards of French broadcloth, invoiced at $1.25 per yard, and weighing 1 \ pounds per yard ? 13. What will be the amount, at compound interest, of $ 340, at 8%, for 1 yr. 3 mo., the interest compounded semi- annually ? 14. If I lose 10% by selling goods at 18^ a yard, for what must they be sold to gain 20% ? 15. I sold 24 J % of my estate, or $ 1372 worth. I am worth, in addition to my real estate, $14,000. How much am I worth in all ? Fractions. 387 REVIEW OF FRACTIONS. 499. Oral Exercises. Give products : 1. 84 x 24 = 25 times 84 - 84 = 2100 - 84. 2. 48x24. 4. 48x49. 6. 84x74. 3. 24x36. 5. 84x49. 7. 48x74. 8. 84 x 241 = 25 times 84 - £ of 84 = 2100 - 42. 9. 48x241 11. 48x24f. 13. 48 x 24f 10. 36 x 241 12. 36 x 24f. 14. 36 x 24|. 15. 48 x 361 = 371. times 48 - 48 = (| of 4800) - 48. 16. 48xllJ. 17. 48x86£. 18. 48 x 37f Give quotients : 1. 36 -*-}. 7. 18I-T-3. 13. 12}-* If 2. 36-i-|. 8. 20£-r-4. 14. 16£-*-lf 3. 36-2}. 9. 17!- -5- 5. 15. 13^-j- 3f 4. 36 -i- f 10. 191 -J- 6. 16. 14} + If 5. 36 -s-lf 11. 16J-5-7. 17. 15} -j-2f 6. 36-r-lJ. 12. 17J-J-8. 18. 17£-i-3f 500. Written Exercises. Find products : 1. 648 x}. 9. 792x25. 2. 976 x if 10. 457x16. 3. 1648 x87f . 11. 1864x250. 4. 2592 x9if 12. 983x51. 5. 2416x875. 13. 1576 x 62f 6. 874x99. 14. 176x23f. 7. 848x125. 15. 1128x875. 8. 375x999. 16. 895 x 44f 388 Chapter Six. 501. Written Exercises. 1. Divide the sum of 6f and 1-| by the difference be- tween 2\ and 3£. 2. What is the difference between the sum of % and | and the product of f and fa ? 3. What is the product of the sum and the difference of 4| and 6J ? 4. Subtract § of J from fj ; and find the value of fa of 16s. 6cZ. 5. Add 7f , } of ft, I of 7| , and «. 6. Keduce f of a square rod to the fraction of an acre, and find the value of ^ of a ton in pounds and ounces. 7. Keduce T 6 ^^ to its lowest terms, and Q * "~ t to its simplest form. ¥ + s 8. Add |j f, f, and J; multiply the sum by fa; and subtract the product from 1. 9. Find the value of 9^ meters at 4-J francs per meter. 10. Divide 2\ by 3£, and add the quotient to fa. 11. Multiply 2 fa by 16f , and divide the result by 1\ of 2f 12. Keduce 7s. 6c?. to the fraction of a pound, and 7 hr. 12 min. to the fraction of a day. 13. Keduce to its simplest form - + * 5 ^. 14. Add together £ £ and ^ of 5| shillings. 15. What fractional part of 7 A. 127 sq. rd. is 5 A. 81 sq. rd. ? 16. What must be added to f of j- to make it equal to AofSf? 17. \ of a number is 148. What is the number ? 18. If 4 of a field is worth $325, what is the field worth ? 19. If J of a house is worth $4900, what is the value of i? Denominate Numbers. 389 REVIEW OF DENOMINATE NUMBERS. 502. Written Exercises. 1. Change 43 yards to rods and a fraction. 2. Change 43 yards to rods and yards. 43 yards -4- 5| yards gives the number of rods. 3. Change 43 yards to rods, yards, and feet. 4. Change 43 yards to rods, yards, feet, and inches. 5. Change 72 yards to rods, etc. 6. Change 66 yards to rods. Change to rods, yards, etc. : 7. 49 yards. 11. 1836 inches. 8. 147 feet. 12. 1837 inches. 9. 1764 inches. 13. 52 yards. 10. 8Jf rods. 14. 49J yards. 503. Change to rods, etc. : 15. 1483 inches. 18. 2796 inches. 21. 3453 inches. 16. 984 inches. 19. 1121 inches. 22. 1278 inches. 17. 1345 inches. 20. 1470 inches. 23. 1576 inches. 504. Add: 24. 4 rd. 3 yd. 1 ft. 25. 5 rd. 4 yd. 2 ft. 9 rd. 4 yd. 2 ft. 5 yd. 1 ft. 3 rd. 1 ft. 6 in. 6 rd. 1 yd. 26. From 8 rd. 1 ft. take 2 rd. 2 ft. 27. Find the difference between 3 rd. 1 yd. 1 ft. and 16 rd. 28. Multiply 5 rd. 4 yd. 2 ft. by 4. 29. Multiply 11 rd. 2 ft. by 10. 30. Divide 30 rd. 5 yd. 2 ft. by 8. 31. Divide 34 rd. 2 yd. by 9. 390 Chapter Six. REVIEW OF COMMERCIAL DISCOUNT. 505. Oral Exercises. When the list price is $ 1, what is the net price after the deduction of each of the following discounts ? 1. 30 and 20%. 4. 50 and 10%. The net price after a deduction ~ ^q j 2Q ol of 30 % is 70 % of .$ 1 , or 70 f. De- ducting 20 % of 70 f leaves 80 % of 6.10 and 5 % . W ' or66 ^- 7. 20 and 20%. • 2. 40 and 10%. m 001 , 1|A-I 7 8. 334 and 10%. The net price is G0% of 90% of 6 $1, or 54% of |1. 9. 20 and 15%. 3. 25 and 40%. 10. 30 and 15%. 506. What single discount is equal to each of the follow- ing double discounts ? 11. 30 and 30%. 15. 40 and 30%. The net price is 70% of 70% of ^ ^ ^ ^ list price, or 40% of list price. The discount is, therefore, 100% 17, 40 an d 5%. -49%, or 51%. ™ -, *** 18 - 50 and 20%. 12. 20 and 25%. ' 13. 25 and 20%. 19 ' 40 and 15%. 14. 15 and 30%. 20. 50 and 15%. Find the single discount equal to each of the following : 21. 50 and 20 and 10%. 22. 40 and 25 and 20%. 23. 10 and 10 and 10%. 24. 30 and 20 and 10%. Interest. 391 507. Written Exercises. Which is the better discount for the buyer ? 1. 30 and 20%, or 40 and 10%. 30 and 20% off = 70% of 80% net, or 56% net. 40 and 10% off s 60% of 90% net, or 64% net. The latter is the better for the buyer. 2. 50 and 10%, or 40 and 20%. 3. 20 and 20%, or 30 and 10%. 4. 20 and 15%, or 30 and 5%. 5. 30 and 15%, or 25 and 20%. 6. 30 and 30%, or 50 and 10%. 7. 40 and 30%, or 20 and 50%. 8. 40 and 5%, or 30 and 15%?. 9. 20 and 50%, or 60 and 10%. 10. 40 and 15%, or 30 and 25%. REVIEW OF INTEREST. 508. Six Per Cent Method. Interest is the product of the principal by the rate ex- pressed as hundredths by the time in years and fraction. The usual method is to perform the operations in the above order. When the rate is 6%, some prefer to first multiply the rate by the time, and to use this as a multiplier of the principal. In finding the product of the rate by the time, advantage is taken of the fact that 6 is a factor of 12 and 30. Six per cent a year is -J per cent a month and -fa per cent a day. When the rate is a different per cent, the interest is first obtained at 6 per cent by this method, and from this result the interest is calculated for the given rate. 39* Chapter Six. 509. Find the 7 mo. 19 da. $2874.35 •218* .47905+ 22.99480 28.7435 574.870 6)$ 627.08735 $104.5145+ 3f 313.5435 78.3859 $391.9294 $391.93 Ans. interest on $2874.35 at 3f% for 3 ft. 6 % for 1 year is for 3 years .18 \ % for 1 month is for 7 months .035 B V/ for 1 day is for 19 days .003$ 6 % for 3 yr. 7 mo. 19 da. is .218 \ Multiplying the principal by .218$ gives the interest at 6 % for 3 yr. 7 mo. 19 da. Dividing this product by 6 gives the interest at 1 %. Multiplying the quotient by 3f gives the interest at 3f %. To find the interest at 6 per cent, multi- ply the principal by 6 times the number of years and J the number of months as hun- dredths, together with % the number of days as thousandths. 510. Written Exercises. Find the interest at 6% on: 1. $ 1428 for 1 yr. 4 mo. 6 da. 2. $ 372.50 for 2 yr. 6 mo. 24 da. 3. $ 1875 for 3 yr. 9 mo. 18 da. 4. $ 240 for 4 yr. 7 mo. 15 da. 5. $ 92.75 for 5 yr. 4 mo. 8 da. 6. $ 817.80 for 10 mo. 19 da. The interest at 6 % plus $ of itself gives the interest at 7 %. The interest at 6 % minus $ of itself gives the interest at 5 %. The interest at 6 % plus $ of itself gives the interest at 8 %. The interest at 6 % minus $ of itself gives the interest at 4 %. The interest at 6 % plus \ of itself gives the interest at 1\ %. The interest at 6 % minus \ of itself gives the interest at 4 \ %. Interest. 393 511. "Written Exercises. Find the amount : 1. $1875.25 for 3 yr. 5 mo. 15 da., at 4|%. 2. $487.50 for 1 yr. 10 mo. 25 da., at 6%. 3. $1206.84 for 2 yr. 1 mo. 16 da., at 5%. 4. $595.00 for 7 yr. 7 mo. 7 da., at 7%. 5. $763.25 for 8 mo. 11 da., at 4%. 6. $685.70 for 19 mo. 5 da., at 51%. 7. $1563.00 for 3 mo. 20 da., at 5%. 8. $998.45 for 87 da., at 4|%. 9. $2575.50 for 149 da., at 3%. 10. $693.27 for 214 da., at 2£%. Find the principal, rate, or time : 11. Principal, $240; interest, $32.04; time, 2 yr. 11 mo. 18 da. Eate ? 12. Eate, 6% ; amount, $717.40; time, 3 yr. 3 mo. 4 da. Principal ? 13. Principal, $360; rate, 3% ; interest, $48.87. Time? 14. Principal, $288; rate, 2£%; amount, $307.22. Time? 15. Eate, 6%; interest, $13.10; time, 4 mo. 11 da. Principal ? 16. Principal, $270; amount, $273.27; time, 3 mo. 19 da. Eate ? 17. Eate, 4£% ; interest, $ 25.11 ; principal, $ 360. Time? 18. Interest, $50.22; time, 3 yr. 1 mo. 6 da. ; rate, Amount ? 394 Chapter Six. REVIEW OF BANK DISCOUNT. 512. Written Exercises. Find face of note, term of discount, rate, discount, or proceeds : By the term is meant the number of days the note has to run, including grace, if any. 1. Face, $600; discount, $6.30; rate, 6%. Term? 2. Term, 33 days; proceeds, $397.80; rate, 6%. Face? 3. Term, 90 days; face, $300; rate, 6%. Proceeds? 4. Term, 21 days; face, $600; discount, $2.45. Rate? 5. Term, 4 months; face, $200; rate, 6%. Discount? 6. Term, 132 days ; proceeds, $ 2689.50 ; rate, 6 % . Face ? 7. Face, $150; proceeds, $147.75; rate, 6%. Term? 8. Face, $1650; discount, $4.95; rate, 6%. Term? 9. Term, 69 days; proceeds, $469.30; rate, 6%. Face? EXACT INTEREST. Exact interest is used by the United States Government in its cal- culations. 365 days are taken to the year. 513. Written Exercises. 1. Find the exact interest of $280 from April 14 to Sept. 6 at 4%. Time, 145 days. Ans. $280 x T ^x }f$. 2. Find the exact interest on $76.65 from March 4 to Dec. 15 at 6 per cent. 3. On $ 384 at 7^ per cent for 75 days. 4. On $438 at 5% from Jan. 1 to March 15. 5. On $109.50 at 4|% for 87 days. 6. On $847.60 at 5% from April 29 to Sept. 20. 7. $584 at 3J% from May 16 to Dec. 1. Unless "exact" or "accurate" interest is specified, use 360 days to the year. Review. 395 MISCELLANEOUS. 514. Oral Review Problems. 1. A has 96 sheep ; B has 28 sheep more than A. How many sheep have both ? 2. There are 56 pupils in one class, 48 in a second class, and 52 in a third class. How many pupils are there in the three classes ? 3. March 29 is what day of the year 1904 ? 4. How far is a man from his starting-point, if he travels due east 150 miles, due west 23 miles, due east again 48 miles ? 5. A body falls 16 feet in the first second, three times as far in the second second, five times as far in the third second. How far does it fall in three seconds? 6. The base of a right-angled triangle is 12 feet, the perpendicular is 16 feet. What is the hypotenuse ? 7. At $35 per month, what will be the rent of a house for 16 months ? 8. A field containing 169 square rods is 13 rods long. What is the perimeter ? 9. 25 packages of sugar weigh together 87£ pounds. How many pounds are there in each ? 10. At 45 miles per hour, how many hours, minutes, and seconds will it take a train to go 230 miles ? 11. How many years have elapsed since the invention of gunpowder, 1356 ? 12. What profit is made on an article bought for $175, less 12%, and sold for $200 ? 13. How many square rods in a field 71 rods long, 81 rods wide ? 396 Chapter Six. 14. Assuming a kilo to be 2\ pounds, how many kilos will be equal to 143 pounds ? 15. A degree of longitude in latitude 45° is about 70% of the length of a degree on the equator. Calling the latter length 69 miles, how long is a degree of longitude in latitude 45°? 16. At $44 per acre, how much land can be bought for 17. A number of marbles divide'd among 29 boys gives each 16 marbles, and leaves a remainder of 26. How many marbles are there ? 18. What is the monthly salary of a clerk who receives $1500 per year? 19. How many revolutions in a mile, 5280 feet, are made by a locomotive wheel 16 feet in circumference ? 20. What is the perimeter of a lot 49 feet wide, 87 feet long? 21. How many bricks 8 inches by 4 inches by 2 inches would make a cubic foot ? 22. 13 is one factor of 1001. Find the other two prime factors. 23. What are the three equal factors of 343 ? 24. What is the square root of 1225 ? 25. At 4 J miles per hour, how long will it take a man to walk 37£ miles ? 26. What will be the cost of 9 dozen hats at $1.33^ each? 27. Paid 92^ for coffee, 48^ for butter, and 18^ for lard. How much was my bill ? 28. I had $ 150. Spent $ 23 for a suit of clothes and $ 48 for tools. How much was left ? 29. What is the area of a field 36 yards by 31 yards ? Review. 397 30. 600 hours equal how many days ? 31. What is the cost of a cow if I pay $630 for 15? 32. How many ounces in 2&±- pounds ? 33. 109J pounds of sugar are divided among 4 people. What is the share of each ? 34. At 1 T 9 7 ^ per pound, how many pounds of iron can 1 get for $ '5.70 ? 35. What is the cost of 51 tons iron at $ 17 per ton ? 36. What will be the average age of 9 boys, each 12 years old, and 6 boys, each 10 years old ? 37. At 42 miles per hour, how long will it take a train to go 882 miles ? 38. At 25^ per hour, what will a man earn in 18 days of 10 hours ? 39. What will ^be the net price of an article whose cata- logue price is $20.00, the discount being 90 and 10% ? 40. A man had $ 181 in bank. What will be his balance after taking out $47 and $33 ? 41. How many feet in 14 rods ? 42. 77 yards are how many rods ? 43. How many square yards are there in a floor lOf yards long and 6^ yards wide ? 44. What is the cost of 372 eggs at 15^ per dozen ? 45. A man owns 3 farms containing 65 acres, 86 acres, and 98 acres, respectively. How many acres does he own ? 46. What is the area of a piece of glass measuring 8J by 6J inches ? 47. What is the value in U. S. money of 50 marks at 23^ cents ? 48. How many francs will a calf cost, if 18 are worth 630 francs ? 398 Chapter Six. 49. A man spends $ 1740 per year. What is the average amount spent per month ? 50. What would 51 pounds of butter cost at 33^ ^ a pound ? 51. Mrs. Allen bought 7 chairs at $4 apiece, 2 tables at $9 apiece, and a carpet for $33. She paid two f 50 bills. How much change was due her ? 52. In what time will any sum of money double itself, at 6%? 53. Find the sum of the prime numbers as far as 12. 54. Interest of $1234, for 30 days, at 6% ? 55. Interest of f 1234, for 6 months, at 4% ? 56. Oil is worth 37^ a pint. How many pints can be bought for $6? 57. Sold oranges for \$ apiece, gaining 50%. How much did they cost apiece ? 58. What will be the cost of 1 pk. 1 qt. 1 pt. of nuts, at 10 ^ per quart ? 59. What is the value of an acre of land, at 10^ per square foot ? 60. 3 desks are bought at $ 10 each, and sold for $ 45. Find the rate of gain. 61. A wheelman sells his old bicycle for $25, and loses 16}%. How much did it cost him ? 62. How much does an agent get for buying 5 bale? of goods at $ 400 each, if he receives 3% for his services ? 63. 10% of 200 is £ of what number ? 64. How old, December 1, 1903, was a boy born November 25,1889? 65. A man has $ 1000 in bank. What will remain after he has taken out $ 478 ? 66. How many hours in the month of January ? Review. 399 67. In how many years, months, and days will $100 amount to $111, at 5%, simple interest? 68. What will 5 tons of granulated sugar cost, at 6 J ^ per pound ? 69. What is the interest of $ 50, for 3 yr. 7 mo. 12 da., at 6%? 70. A farmer makes 675 gallons of cider. He has but 12 barrels, each of 45 gallons' capacity, to store it in. How many more such barrels does he need ? 71. What will be the cost of 36 yards of cloth, at $2.75 per yard ? 72. Add 3794 and 2975. 73. What is the bank discount on a sixty-days note for $400, at 6% ? 74. Change ^-toa decimal of three places. 75. How much wood in three piles containing, respec- tively, \ of a cord, ^ of a cord, and \ of a cord ? 76. What is the percentage of gain in case of railroad stock bought for $ 80 per share, and sold for $ 90 per share ? 77. A dealer sold flour at a profit of 50^ a barrel, and gained 10%. What was the cost ? 78. At 10 ^ a quart, what are 3 bu. 1 pk. 5 qt. of chest- nuts worth ? 79. How many yards in 288 inches ? 80. What decimal of a number is -f per cent of it ? 81. If a broker buys for me 5 shares of railroad stock whose par value is $ 100, what is his brokerage at \% ? 82. If I sell 10 shares of railroad stock for $ 1090, and gain 9% on the cost, what was the cost? 83. What is the interest of $ 660, for 3 months, at 4% ? 4-00 Chapter Six. 84. What per cent does a merchant lose by selling goods at | of their cost ? 85. What principal at 6% simple interest will gain $36 in 1 year and 6 months ? 86. What per cent is gained on goods sold at double the cost? 87. What is 8% of 50 bushels ? 88. $3000 is 11£% of my property. How much am I worth ? 89. What is the interest on $ 700, for 15 days, at 6% ? 90. Bank discount on a 65-day s note for $ 1000, dis- counted at date ? 91. At what rate will $ 2 gain $ 20 in 5 years ? 92. A capitalist wishes to realize 5% on money invested in stock. What must be the annual dividend on stock cost- ing 300, in order to produce this rate ? 93. What will be the taxes on property assessed at $25,000, the rate being $16 per $1000 ? 94. Find the compound interest on $ 1000, for two years, at five per cent, interest compounded annually. 95. What will be the net cost of an article marked $8, on which a discount of 50, 25, and 10% is allowed ? 96. Find the "list" price of an article sold for $ 10 after a discount of 50 and 50 per cent had been deducted. 97. Paid 90 ^ for an article. The discount is 25 and 25 per cent. What is the list price ? 98. One boy can do a certain piece of work in 2 hours, a second boy requires 3 hours, a third needs 6 hours. How long will it take the three working together ? 99. Sold a cow for $ 60, losing 25 % • What was the loss ? 100. Sold a cow for $60, gaining 25%. What was the gain? Review. 401 101. Sold two horses at $240 apiece. On one I gained 20%, on the other I lost 20%. Did I gain or lose on both, and how much ? 102. What is the interest of $1500, for 60 days, at 6% ? 103. How many years will it take $20 to gain $20 at 5 per cent simple interest ? 104. John has $60, James has $80. James has what per cent more money than John ? John has what per cent less money than James ? 105. I is what per cent of J ? J is what per cent of f ? 106. Two men working together can finish a piece of work in 8 days ; one can do it in 12 days. How long would the other take to do the work ? 107. How many yards of cloth at $3.75 per yard can be bought for $90? 108. A puts $600 into business; B, $400; the profits are $500. What is the share of each ? 109. Two boys hire a camera for 26 weeks, paying $5.20. How much should be paid by the boy that uses it 12 weeks ? 110. New Orleans is 90° west of Greenwich. When it is 2 p.m. at the latter place, what is the time at New Orleans ? 111. Find the discount, at 6%, on a note for $300, that has 48 days to run. 112. What will be the cost of 84 yards of cloth at 49 ? a yard ? 113. Two men hire a pasture for $84. One puts in twice as many head of cattle as the other. What should each pay? 114. A base-ball club won 17 games, and lost 13 games. What per cent of its games did it win ? 115. What per cent of 4 is 64 ? 116. 2| is what per cent of 3£? 117. How many acres in a rectangular farm 1 mile long, J mile wide ? 402 Chapter Six. 118. What per cent of the "list" price is paid by a buyer who receives a discount of 20 and 10 per cent ? 119. A tank is filled by two pipes, one of which can fill it in 6 hours, and the other in 8. How long will it take both together to fill the tank ? 120. Find the interest on $80, for 72 days, at 6%. 121. A man sold a wagon for $420, which was 16% less than it cost. How much did he lose ? 122. A kilo is 2.2046 lb. How many pounds in 1000 kilos ? 515. "Written Keview Problems. 1. What number subtracted 88 times from 80.005 will leave .013 as a remainder ? 2. At what price must an article that cost $30 be marked so that after deducting 40% from the marked price, 30 % profit may be realized ? 3. Write a ninety-days promissory note for which you should get $ 240 at the bank, discount being 6%. 4. If a horse dealer buys a span of horses at 10 per cent less than their value, and sells them at 10 per cent more than their value, what per cent does he make ? 5. If a boy buys peaches at the rate of 5 for 2 cents, and sells them at the rate of 4 for 3 cents, how many must he buy and sell to gain $ 4.20 ? 6. What is the difference between the compound interest on $ 5000, for 3 years, at 5%, and on $ 10,000, for 1£ years, at the same rate ? 7. A can do a piece of work in 27 days, and B in 15 days ; A works at it alone for 12 days, B then works alone for 5 days, then C finishes the work in 4 days. In what time could C have done the work by himself ? Review. 403 8. A room is 15 feet long, 10 feet broad, and 9 feet 9 inches high. Find the cost of painting the walls and the ceiling, at Is. 9d. a square yard. 9. What is the value of a pile of wood 40 feet long, 4 feet wide, and 5 feet high, at $ 5.30 a cord? 10. By buying a cargo of coal at $6 per ton, and selling it at $ 8 a ton, I gained $ 198. How much did I pay for it ? 11. Make out a receipted bill for the following : 325 yards of silk at $ 2.25 per yard ; 296 yards of lace at $ 1.50 per yard ; 480 yards of ribbon at 9 0.50 per yard ; 45 dozen pairs of gloves at $ 15 per dozen pairs. 12. My dividend is 8|, quotient 94. What is the divisor ? 13. I gave away ^ and -§ of 41 bushels of chestnuts. What % was left ? 14. The perimeter of a square field is 16 rods. WTiat is the field worth, at 8J^ a square foot? 15. A broker's bill for cotton at 4J^ per pound and his commission for buying at 21% was $1998.75. How many bales of 400 pounds each did he buy, and what was his commission ? 16. I sold 80 yards of broadcloth for $ 240, thereby losing 20% on the cost. For what should I have sold it per yard to have gained 15 % on the cost ? 17. A man bought 60 casks, of 65 gallons each, for $ 1542; 80 gallons leaked out. For what must he sell the remainder per gallon to gain 12 J % on the cost? 18. Each of two men sold his horse for $ 180. One made 20%, the other lost 20% on the cost. Cost of each horse? 19. A man agrees to dig a cellar 30 feet long, 24 feet wide, and 6 feet deep. What % of the work is to be done when he has removed 144 cubic yards ? 404 Chapter Six. 20. A man bought 672 yards of cloth at $ 1.25 a yard. He sold it immediately for $ 2.25 a yard, receiving in pay- ment a 60-day s note for the amount, which he had dis- counted at a bank at 7%. How much money did he make ? 21. What will it cost to fill in a street 55 feet wide, 600 feet long, and 5| feet below grade, at 40 ^ a cubic yard ? 22. The quotient arising from the division of 6985.473 by a certain number is 51, and the remainder is 68.853. What is the divisor ? 23. What is the value of the following? 8flr + **-«t . 1 xftxf 2f + l|-3i " fxfxi 24. In going 1 mi. 94 rd. 2 yd. 1 ft., a carriage wheel makes 526 revolutions. What is the circumference of the wheel ? 25. On a note dated Oct. 16, 1903, for $2650, with in- terest at 6 per cent, the following payments were made: Jan. 28, 1904, $ 575 ; May 22, 1904, $ 25 ; and Aug. 4, 1904, $ 948. 'What was due Nov. 25, 1904 ? 26. A grocer pays 18 ^ per pound for coffee and roasts it, the coffee losing 10 per cent of its weight in the process. What must he charge per pound for the roasted coffee in order to make a profit of 20 per cent, allowing 4 per cent for bad debts ? Note. — 96% of the price he receives per pound must be 20% more than the rate of 18 f for ^ lb. 27. A merchant imported from Bremen 32 pieces of linen of 32 yards each, on which he paid for the duties, at 24 per cent, $ 122.16, and other charges to the amount of $ 40.96. What was the invoice value per yard, and the cost per yard after duties and charges were paid ? Review. 405 28. A garrison of 1200 men is provisioned for 100 days. At the end of 30 days, 600 men are withdrawn, and at the end of 60 days, 900 men are added. How long will the provisions last ? 29. What will be the result, if £ of f of 3 J- be multiplied by £ of itself, and the product be divided by £ ? 30. A collector of internal revenue deposited in the treas- ury $ 762,742.50, retaining 2\ per cent of the amount col- lected. What amount did he collect ? 31. What is the duty on 25 tons 2 cwt. 3 qr. of iron at % 8 per ton ? (1 ton = 2240 lb.) 32. An importer sold a part of a cargo of tea at 30 cents a pound and made a profit of 20 per cent. What per cent did he make on the remainder of the cargo, which he sold at 40 cents a pound ? 33. Divide % 4.14 among Thomas, Richard, and Henry in such a way that Henry shall receive 3 cents for every 5 cents that Thomas gets, and Richard shall receive 2 cents for every 5 cents that Henry gets. 34. Reduce 272 liquid quarts to dry quarts. 35. A pipe discharging 3 gallons 1 pint a minute fills a tub in 4 minutes 20 seconds. Another pipe discharges 83 quarts a minute. If both pipes discharge together into the tub, how long will they take to fill it ? 36. William Wilson sold goods to the amount of % 1000. One-half of his sales showed a profit of 25 per cent on the cost, and the remaining half a loss of 16| per cent on the cost. Required the total cost of the goods. 37. If I sell I of my farm for f of what the farm cost me, what is my gain per cent ? 38. Which is the higher rate of freight on wheat, $.16 per hundred or $ .10 per bushel (60 lb.), and what per cent ? 406 Chapter Six. 39. Write in words : (a) .267; (6)200.067; (c) flftj ((f) 200^fo. 40. If 40 per cent of the selling price of an article is profit, what is the per cent of gain on the cost? 41. What number added to 4 J times itself will equal 60 J ? 42. Divide J by .00003J. 43. Keduce to lowest terms (a) i|-f| ; (6) |f|. 44. If 4 men eat 64 pounds of bread in 2 weeks, how many pounds will 16 men eat in 7 weeks at the same rate ? 45. Divide .75 of 17f by £ of .035. 46. Find the cost of 3846 pounds of hay at $15 per ton. 47. Find the cost of plastering the walls and the ceiling of a hall 72 feet long, 50 feet wide, and 22 feet high, at 18f •cents a square yard, allowing 972 square feet for openings •and baseboards. 48. A certain quantity of paper will make 4000 copies of an octavo book (8 pages to the sheet). How many copies ■of a 12mo book (12 pages to the sheet) will the same paper make? 49. Find the diagonal of a square park containing 20 acres. 50. Bangor, Maine, June 24, 1904. On demand, I promise to pay Joseph I. Totten, or order, Two Thousand Five Hundred Fifteen Dollars, with interest, value received. $2515^. Charles Hettesheimer. $1541.01 was paid Jan. 1, 1905. Find the amount due Aug. 15, 1905. 51. How much does it cost annually to insure the "Celtic" for $1,525,000, if 2J% is paid for the insurance ? 52. $ 150 is paid an agent for purchasing 1200 barrels of ■flour on a commission of 2£%. How much was paid per barrel for the flour ? Review. 407 53. An agent received $2562.50 for purchasing land at $62.50 per acre, and his commission of 2|%. How many acres did he buy ? 54. Reduce the fraction -3 — 4S + « — I* 5 • 55. Divide J by 2.5, to the quotient add the divisor, and from that sum subtract the dividend. Give the fractional part of the answer in a decimal. 56. If the interest on $300 for 1 yr. 8 mo. is $36, find what would be the interest on $ 212.50 for 3 yr. 4 mo. 24 da* at the same rate. 57. Reduce .0468 T. to a compound number. 58. Find the prime factors of 20,930. 59. A man paid $ 999 for the rent of a house from June 29, 1903, to May 5, 1905. What was the rent per year? 60. What per cent of 3 lb. 7 oz. is 7 lb. 9 oz. ? 61. At 50 cents per running yard, what will be the cost of fencing a square field containing 10 acres ? 62. At the rate of 20 problems an hour for A, and 15 in 55 minutes for B, in what time can both together solve 100* problems ? 63. Find the entire surface of a cube whose edge meas- ures 15 inches. 64. A dealer buys books at $ 1.50 each, less 33J and 10 per cent. At what price per copy must he sell them to gain 43£ per cent? 65. Abraham Lincoln died at the age of 56 yr. 2 mo. 3 da.,, after serving as President 4 yr. 1 mo. 11 da. Give the date of his birth, the date of his inauguration being March 4, 1861. 408 Chapter Six. 66. A dealer buys 150 barrels of flour. He sells one- third of it at $ 4.50 per barrel, losing 10 per cent. The remainder he sells at a profit of 6 per cent. What is his net gain or loss ? 67. Sixty per cent of 66% per cent of a number equals 810. What is the number ? 68. A ladder 40 feet long is so placed in a street, that without being moved at the foot, it will reach a window on one side 33 feet, and on the other side 21 feet from the ground. What is the breadth of the street ? 69. Four men hired a coach for $ 13, to convey them to their respective homes, which were at distances from the place of starting as follows: A's 16 miles, B's 24 miles, C's 28 miles, and D's 36 miles. What ought each to pay ? 70. What is a pile of wood 8 feet long, 7 feet wide, and 5 feet high worth, at $ 4.50 per cord ? 71. When bank stock sells at a discount of 1\ per cent, what amount of stock, at par value, will % 3700 purchase ? 72. The pound sterling is worth $4.8665. How much U. S. coin would it require to pay a debt of £ 780 18s. lid. ? 73. A merchant imported 120 tons of English iron, cost- ing 1£ pence per pound, on which he paid a duty of 20 per cent. The freight was 5 shillings sterling per ton. What was the total cost in U. S. currency ? (1 ton =2240 pounds. £1 = $4.8665.) 74. How many rods of fence are required to enclose a square lot whose area is 5184 square feet ? 75. Property worth $6000 is insured for { of its value, at f of one per cent. What will be the loss, including pre- mium, in case of total destruction by fire ? 76. How many acres of land, in the form of a square, may be enclosed by 160 rods of fence ? Review. 409 77. Find the square root of .441 correct to two decimal places. 78. Reduce 17 lb. 10 oz. Avoirdupois weight to pounds, ounces, pennyweights, and grains, troy weight. (1 pound Avoirdupois = 7000 Troy grains.) 79. Reduce |4if to ^s lowest terms. 80. Find the solid contents of a cube, the area of one face of which is 256 square feet. 81. A car contains 21,643 pounds of wheat. Find the value of the load at 92 ^ per bushel of 60 pounds. 82. Find the area of a triangle whose base is 22 ft. 8 in., and altitude 19 ft. 9 in. 83. The list price of a certain stove is $ 38, and the retail dealer is allowed commercial discounts of 20 per cent, 5 per cent, and 3 per cent. What price does he pay for the stove ? 84. If a ton of coal lasts a family 21 days, what will be the cost of coal used by it from Oct. 17, 1904, to April 25, 1905, exclusive of either day named, at $ 4.50 per ton ? 85. Find the cost of a pile of 4-foot wood, 27 feet long and 6 feet high, at $ 5.50 per cord. 86. How many rods of fence will be required to enclose a field in the form of a right-angled triangle, whose area is 13i acres and whose base measures 48 rods ? 87. What is the balance of a bill of $ 64.50, after two discounts have been made; the first of 20% on the $ 64.50, the other of 5 % on what then remained ? 88. There was shipped to Liverpool from New York in one week $ 6,870,205 in specie. What amount of English currency could be bought with it ? (£ 1 = $ 4.8665.) 89. What is the freight on 9860 pounds iron at $ 1.75 per ton? 41 o Chapter Six. 90. What is the value of 10 lb. 7 oz. 16 pwt. of gold at 9 -75 a pennyweight ? 91. The dividend is 6171, the quotient 17, the remainder 102. What is the divisor ? 92. Divide the L. C. M. of 132 and 156 by their G. C. D. 93. The product of three numbers is .0728 j one of them is 1.3, another .07. Find the third. 94. If 5 men can make 38 rd. 5 yd. of fence in a day, how much can they build in 30 days ? 95. The distance from New York to New Haven being 73 mi. 8 rd., at what rate does a train run per hour to cover the distance in 2 hr. 10 min. ? 96. Eeduce 4 da. 4 hr. 48 min. to the decimal of a week. 97. After 4 per cent of a flock of sheep had been killed by dogs, and 68 had been sold to a butcher, four-sevenths of the original flock were left. Required the number of sheep in the flock at first. 98. Six men bought a ship worth $ 45,268, for which A paid \ of the whole, B J, and the others paid the remainder equally. How much did each of the latter pay ? 99. A man agrees to dig a cellar 30 feet long, 24 feet wide, and 6 feet deep. What per cent of the work has he done when he has removed 16 cubic yards ? 100. How many boards 16 feet long, and 4 inches wide, are required to floor a room 48 feet long, and 32 feet wide ? 101. How much walking does a man save by crossing diagonally a field 28 rods long, and 21 rods wide, instead of going along the end and the side ? 102. In order to have an annual income of $2500, what sum must be invested at 5% ? 103. At $2 a rod, what is the difference in the cost of fencing a lot of land 20 rods square, and another lot contain- ing the same area which is 40 rods long ? Review. 41 1 104. If a man owning 45% of a steamboat sells J of his share for $ 5860, what is the value of the whole boat ? 105. A farmer having 6 bu. 8 qt. of cranberries lost by- decay 7 pk. 7 qt. What % had he left ? 106. Sold tea for 114% of its cost, and made a profit of 7^ a pound. Find selling price. 107. In § of an acre of land how many building lots, each 60 feet by 121 feet? 108. I bought a store for a certain sum, and after paying a tax of 2\°/o on the cost and \) 14. The sum of three numbers is 180. The first is double the second, and the third is three times as large as the sum of the other two. What are the numbers ? 420 Chapter Seven. 15. Mr. Smith paid 81 cents for sugar and flour, the same quantity of each. For the sugar he gave 5 ^ per pound, and for the flour 4/ per pound. How many pounds of each did he buy ? 16. The length of a rectangular field is 24 rods, its breadth is x rods, its area is 456 square rods. Find the value of x. 17. It takes 340 feet of fence to enclose a square lot. What are the dimensions of the lot ? 18. Mrs. B. divides $ 120 between her son and her daugh- ter. She gives the latter twice as much as she gives the former. What is the share of each ? 19. The earnings of a man and his son during January amounted to $ 175, both having worked the same number of days. The father's wages were $ 4 per day, and the son's wages were $ 3 per day. How many days did they work ? 20. The sum of $240 is divided among four children, two boys and two girls. Find the share of each, if each girl's share is double that of each boy. 21. A man worked twice as many days as his son. Their combined earnings amounted to $ 165. Find the number of days each worked, if the father earned $4 per day and the son three-fourths as much per day. 22. A boy's bank contains 78 tf in dimes, nickels, and cents. There are twice as many nickels as there are dimes, and three times as many cents as there are nickels. How many are there of each ? 23. I paid 75^ more for a roll of 15-cent ribbon than I did for a roll of 12-cent ribbon of the same length. How many yards did each roll contain ? 24. A rectangular field whose length is four times its breadth requires 250 rods of fence to enclose it. What are the dimensions of the field ? (Make diagram.) Algebraic Equations. 421 25. A girl paid 60 cents for a speller and a reader, the cost of the former being one-third that of the latter. Find the cost of each. 26. The sum of two numbers is 72, and the smaller is one-fifth of the other. What are the numbers ? Let x = smaller. 27. Mary, Susan, and Jane have 54 hickory nuts. Susan has one-half as many as Mary, and Jane has as many as the other two. How many has each ? Let x = number Susan has. EQUATIONS. 524. An expression like 3 x + 16 = 28 is an equation. 3 x -f- 16 is the first member of the equation. 28 is the second member of the equation. What is the part of the equation to the left of the equal- ity sign called ? What is the second member of an equa- tion? What sign is between the two members? What does this sign show about the value of the two members ? What is an equation ? 525. Written Exercises. Suppose a = 2 and 6 = 3. Complete the equations : 1. ab + ? = 7. 6. ab + b = 5 + ?a. 2. a + 6-? = 4. 7. 17 - ab = 5a + ? 3. ?a + 6 = ll. 8. 17-a6-? = 5a. 4. ab = a + b + ? 9. 12 + a6 = 26 + ?a. 6. a& = 12-?6. 10. 12 + a6-?a = 26. 422 Chapter Seven. CLEARING OF FRACTIONS. 526. Oral Exercises. 1. One-fifth of a number is 4. What is the number ? 2. £ of a number is 8. What is £ of the number ? 3. % of a number is 12. What is the number ? 4. ^ of a number is 10. What is J of the number ? 5. If | of a number is 30, what is the number ? 6. One-half a number added to \ of the same number equals what fraction of the number ? 7. One-half a number added to \ of the same number equals 30. What is the number ? 8. One-third of a number -f- one-sixth of the number = what fraction of the number ? 9. One-third of a number added to \ of the number = what fraction of the number ? 10. \x + \ x = what fraction of x? |+|=? 527. When x = 32, find the value of three-fourths of x ; When — (3 x divided by 4) = 24, what is the value of 3z? 0f»? Find the value of y, when | = 12. Of 2y, when ^ = 24. 4z ^ Given the equation —- = 20 ; by what whole number can o we multiply the first member to get rid of the fraction ? If we multiply one member of an equation by any number^ what must we do to the second member in order to preserve the equality ? If equals are multiplied by equals the products are equal. Algebraic Equations. 423 528. Sight Exercises. Give values of x, y, z, etc. : 1. |=4. , g+j-u 9 . ?+|= 8 . 9 . | = 8. 6 . | + |=5. 10. f + ^=32. 3. |=7. 7. | + |=10. 11. f + |=9. 4 Jo 4 o 4. ^ = 21. 8. | + | = 7. 12. | + ^ = 9. 13. |-|=2. 15. |-?=6. 14. §-£ = 8. 16. 2_? =5 . 3 12 2 7 529. Written Exercises. Find the value of the unknown quantity (x). Multiplying by 12, we have 6x + 4x + 3x = 312. 2 . .+1+5-44. • . Multiply by 6. 6x + 3x + 2x = 264. To clear an equation of fractions multiply each term of both members by the least common denominator of the fractions. 3. ^ + ^=35. 6 * t* + f*«fl2. 23 7. ^ + ^=102. 4. * + *=49. 3 4 3 4 8. 21 x =115. 5. * + ^ = 28. 9. 1^-^=48. 2 3 5 3 424 Chapter Seven. 10. a?- — = 156. 19. 75 a; 33 x _ gl 40 100 50 11. 3fz = 116. 20. 8 a; 2 a; ^ oa — - — = ldb. ¥= 27 - 3 5 12. 21. 2^3^4 13. Ux=x27. 2 22. a;_^_? = 37. 14. il^=22. 2 3 4 4 a; 2 a; . 3 a; , 23. — 2< 15. 2fa; = 44. 5 9 4 16. 2 a; -f — = 33. 4 24. a; . £ x x Krt 17. 3£a;-2fa; = 45. 25. aj_^ = 80. 4 18. a;+f=24. 26. a; -f 2a; + — = 24. 5 7 530. Written Problems. 1. Divide 100 into two parts, one of which shall be 1J times the other. 2. After losing ^ of his money, a man has $714. How many dollars had he at first ? (* -|=714) 3. A horse was sold for $240, the seller thereby gaining one-third of what he originally paid for it. How much did he pay for it ? K) 4. One-half of a number added to one-fourth of the same number equals 66f . What is the number ? 5. The difference between f of a number and £ of the same number is 15. Find the number. 6. One number is £ of another. Their sum is 55. What are the numbers ? Algebraic Equations. 425 7. Find a fraction equivalent to J, the sum of its numer- ator and its denominator being 60. (Let 7 x = numerator and 8 x = denominator.) 8. Find a fraction equivalent to j-, the difference between its numerator and its denominator being 24. 9. The sum of two numbers is 480, and the quotient ob- tained by dividing the greater by the less is 7. What are the numbers ? 10. Find two numbers whose difference is 522 and whose quotient is 30. 11. A boy buys apples at 2^, pears at 3^, and oranges at 4^, the same number of each. How many of each does he buy, if he pays 81 4 for all ? 12. A girl bought 70 cents' worth of peaches and plums. She paid 3^ each for the peaches and 2^ each for the plums, buying four times as many of the former as of the latter. How many of each did she buy ? 13. $ 1500 is divided among three persons, the second of whom receives three times as much as the first, and the third three and one-half times as much as the first. Find the share of each. 14. A farmer paid for a cow three-sevenths as much as he paid for a horse. How much did he pay for each, if the latter cost $80 more tl- n the former ? j 15. Three times a man's money increased by two-thirds of his money is equal to $ 1100. How much money has he ? 16. After giving away f of his marbles 'and losing \ of them, Joseph has 24 left. How many had he at first ? 17. Bought a coat, a hat, and an umbrella for $15, pay- ing for the hat 1^- times as much as for the umbrella, and for the coat 3^ times as much as for the hat. Find the price of each. 426 Chapter Seven. 18. A merchant purchased two pieces of cloth for $240, paying for one piece twice as much per yard as for the other. The former contains 36 yards and the latter 48 yards. How much does he pay per yard for each ? 19. A farmer sold 4 times as many cows as horses, receiv- ing for all $840, at the rate of $40 for a cow and $120 for a horse. How many of each did he sell ? 20. The weight of a team with a loaded wagon is 5500 pounds. The wagon weighs f as much as the load. The team weighs twice as much as the wagon. How many pounds does the load weigh ? 53i. Oral Exercises. Give values of x, y, z, etc.: 1. a + 15 = 21. 7. Sy + 6 = 15. 2. 22/ + 15 = 21. 8. 7 y - 13 = 15. 3. 0-7 = 21. 9. 9 y + 13 = 58. 4. 4w-7 = 21. 10. 3y-10 = 56. 5. | + 3 = 8. 11, 5^+1 = 7. 4 6. --3 = 12. 12. i^-i=n. 532. If x + 15 = 21, x = 21 - what ? When x- 7 = 21, x = 21 + what ? If in the equation 2 x -f 15 = 21, we take away 15 from the first member, what must we do to the second member to preserve the equality ? If equals are subtracted from equals, the remainders are equal. ' By transposing we mean bringing the unknown quantities (jr, /, z, etc.) to one side of the equation and the known quan- tities to the other. Note. — In bringing a quantity from one side of the equation to the other, the sign of the quantity is changed. Algebraic Equations. 427 533. Written Exercises. Find values of the unknown quantities. Note. — Clear of fractions when necessary ; then transpose. 1. x + 37 = 56. 5. x + 3 x = 25 + 11. 2. 4a;-5 = 83. 6. 5 x = x + 40. 3. 3 a; -43 = 98. 7. 3 x - 20 = x - 8. 4. 7x + 13 = lll. 8. 12 - 3 x = 45 - 4 x. 9. 3z-6 = 48 + z. 15. 7rc-5a; = 20 + a;+4 0. 3z + 6 = 9-2a + 12. 16. 6x -14 = 16 + x 1. 2z-2-16 = a; + 10. 17. 2z-ll+6a;-60=5a; 2. --8 = 24. 18. l+|- 6 = 10 - 3. ^ + 4-7 = 21. 6 19. 2*-6 = 16 + |-|. 14. | + ^ = 10 + 5. 20. 2z + ^-| = ^ + 27. 534. Written Problems. 1. The sum of three numbers is 51. The second is 5 less than the first, and the third is 10 less than the first. What are the numbers ? Let x = first number, x — 5 = second number, x — 10 = third number ; x + x - 5 + x - 10 = 51. Transposing, x + x + x = 51 -f 5 + 10, 3 x = 66, x = 22, first number, a; — 5 = 17, second number, X — 10 = 12, third number. 428 Chapter Seven. 2. Add 45 to four times a number, and you will have seven times that number. What is the number ? (7 x = 45 -f 4 x.) 3. Nine times a number less 27 equals six times the number. Find the number. 4. Two boys have together 48 marbles. One has 18 more than the other. How many has each? (x, x+ 18.) 5. The length of a rectangular lot is 75 feet more than the breadth. The distance around it is 250 feet. What are its dimensions ? 6. A piece of land containing 86 acres is to be divided into two fields, one of which shall be 8 acres larger than the other. How many acres in each field ? 7. At a certain election 2436 votes were cast for two candidates, the successful one receiving 318 more votes than his opponent. How many votes did each receive ? 8. A man, being asked his age, replied that if he were half as old again and 7 years more he would be 100. What was his age ? 9. The sum of two numbers is 96, and their difference is 72. Find the numbers. (Let x = less, x + 72 = greater.) 10. After paying £ and J of my debts, I still owe $ 45. How much did I owe originally ? s_?_? = 45. 3 4 11. Divide 45 into two parts, one of which shall be 6 less than twice the other. 12. William has $5 more than John, and three times William's money added to five times John's would be $ 103. How many dollars has each ? Algebraic Equations. 429 13. I bought 3 cows and 4 horses for $635, paying $ 80 apiece less for the cows than for the horses. How many dollars apiece did I pay for each ? 14. Mary has a dollar in dimes and five-cent pieces. She has 11 more of the latter than of the former. Find the number of pieces of each denomination. 15. Divide 100 into two parts whose difference shall be 48. 16. In a class of 54 pupils, the girls outnumber the boys by 12. How many are there of each? 17. $ 18,000 is divided among three persons, the second of whom receives 9 2400 more than the first, and the third of whom receives $2400 more than the second. Find the share of each. 18. The greater of two numbers is 11 more than 3 times the less. Their difference is 33. What are the numbers ? 19. A boy spent a dollar for postal cards, 2-cent stamps, and 5-cent stamps. He bought 15 more 2-cent stamps than 5-cent stamps, and 15 more postal cards than 2-cent stamps. How many of each did he buy ? Let x = number of 5-cent stamps, then x + 15 = number of 2-cent stamps, x -f- 30 = number of postal cards. 5 x = value of 5-cent stamps, 2 x + 30 = value of 2-cent stamps, x + 30 = value of postal cards. 5£-f-2s + 30 + a + 30 = 100 20. A farmer has 88 head of stock — horses, cows, and sheep. He has 17 more cows than horses, and the number of sheep is 22 greater than that of the cows and horses together. How many are there of each ? 430 Chapter Seven. ADDITION OF ALGEBRAIC QUANTITIES. 535. Oral Exercises. Add: 1. 2 fours 2. 6 hundredths i 3. $4 4. 3f 5. 7 a? 3 fours 8 hundredths $5 5? 4a? 4 fours 10 hundredths $7 *f 2x 5 fours 12 hundredths $3 9^ 5x ? fours ? hundredths i? U ~x When no coefficient is expressed, 1 is understood. Thus, abc = 1 abc. Where nc > sign is expressed, + is understood . 6. — 2a 7. + 3x 8. -5xy 9. 9 abc 10. — 24:xyz - 4a + 4a; — 4:xy 15 abc — 5xyz - 6a + 5a? — xy 6 abc - xyz - la +10 a; —2xy abc —15xyz -19 a + ? x -?xy ? abc — ? xyz NEGATIVE QUANTITIES. 536. Suppose three men as follows : The first man has $5 and owes nothing. The second man has $5 and owes $5. The third man has nothing and owes $5. The first man is worth $5. The second man is worth nothing. The third man is worth 5 less than nothing. So we may say he is worth — $ 5. 537. Quantities like — $5, —17, and —2a are called negative quantities. What sign precedes a negative quantity ? Quantities with a plus sign expressed or understood are called positive quantities. Algebraic Equations. 433 SUBTRACTION OF ALGEBRAIC QUANTITIES. 541. Preliminary Exercises. * 1. A man sold a horse for $ 100 at a gain of $ 25. Find the cost. (Cost = selling price — gain.) $ 100 = selling price $ 100 subtract 25 = gain or add — 25 remainder $ 75 = cost $ 75 2. A man sold a horse for $ 100 at a gain of — $ 25. Find the cost. $ 100 = selling price $ 100 subtract - 25 = gain or add -f 25 $ 125 = cost $ 125 In the first of the above examples, subtracting 4- $ 25 is the same as adding — $ 25. In the second of the above examples, subtracting — $ 25 is the same as adding + $ 25. We changed the first example from subtraction to addition by changing the sign of the subtrahend from + to — . We changed the second example from subtraction to addition by changing the sign of the subtrahend from — to +. To subtract in algebra, change the sign of the subtrahend and proceed as in addition. 3. Add 7 and - 3. 6. Add - 7 and 3. 4. From 7 subtract - 3. 7. Add - 7 and - 3. 5. From — 7 subtract 3. 8. From — 3 subtract — 7. 9. Subtracting — 7 is the same as adding what ? 10. Is a positive quantity increased or decreased by sub- tracting a negative quantity ? Note. — When you become familiar with the process of subtraction it will not be necessary to write the subtrahend with a changed sign. You can conceive the sign changed and add. 43 2 Chapter Seven. We may put down the above statements thus : $ 6 $-3 -3 2 4 -2 8 4 -2 -1 _I -2 $20 $-2 In the first example we add all the positive quantities, $ 6 -f $ 4 + $8 + $7 = $25. Then we add all the negative quantities, — $3 — $ 2 = — $ 5. Adding $ 25 and — 1 5 the result is $ 20. In the second example we add all the positive quantities, and get $ 6. The sum of the negative quantities is — $ 8. Adding $ 6 and — $ 8 the result is — $ 2. Can you give the rule for addition where the quantities have different signs ? Which sign does the sum take ? 540. Written Exercises. Add: 1. —2a 2. 7x 3. — 5xy 4. — 9abc 5. — 24an/z — 4:xy 15 abc 5 xyz xy 6 abc xyz 2xy — abc 15 xyz 6. 3a; + 14, —7a; + 9, -23, 4a; -5, -2a;, and 3a; + 11. 3a; + 14 Write like quantities in the same column. __ j x , g Find the sum of the positive terms, also —23 the sum of the negative terms; subtract 4#— 5 the less from the greater, and prefix the __2a; sign of the greater. 3 a; + 11 7. 4a + 3a;, —2a, —7a; — 3a, —5a;, — 9a + a;. 8. -36 + c, 4a + 6 6, 56-9 c, -3a, -2a-3& + 4& 9. ix-S, -a; + 4, — \x — 3, 7a; + 16, -5a;-10. 10. 4a; + 23, -%x + 2\, -|a; + ll, -a; + 5, 9a;-3. -2a 2. 7x -4a — 4a; — 6a -2a; la 5x Algebraic Equations. 433 SUBTRACTION OF ALGEBRAIC QUANTITIES. 541. Preliminary Exercises. • 1 . A man sold a horse for $ 100 at a gain of $ 25. Find the cost. (Cost = selling price — gain.) $ 100 = selling price § 100 subtract 25 = gain or add — 25 remainder $ 75 = cost $ 75 2. A man sold a horse for $ 100 at a gain of — $ 25. Find the cost. 1 100 = selling price $ 100 subtract — 25 = gain or add + 25 $ 125 = cost $ 125 In the first of the above examples, subtracting + $ 25 is the same as adding — $ 25. In the second of the above examples, subtracting — $ 25 is the same as adding + $ 25. We changed the first example from subtraction to addition by changing the sign of the subtrahend from + to — . We changed the second example from subtraction to addition by changing the sign of the subtrahend from — to + . To subtract in algebra, change the sign of the subtrahend and proceed as in addition. 3. Add 7 and - 3. 6. Add - 7 and 3. 4. From 7 subtract —3. 7. Add —7 and —3. 5. From — 7 subtract 3. 8. From — 3 subtract — 7. 9. Subtracting — 7 is the same as adding what ? 10. Is a positive quantity increased or decreased by sub- tracting a negative quantity ? Note. — When you become familiar with the process of subtraction it will not be necessary to write the subtrahend with a changed sign. You can conceive the sign changed and add. 434 Chapter Seven. 542. Sight Exercises. 1. /What is the difference between + 52° and +33°? 2. Between + 90° and - 10°? Show by a diagram. 3. A has $600, B owes $400. What are they worth together ? ^ + g 600 ^ + (_ $ 40 0) = ? 4. How much better off is A than B ? (+$ 600) -(-$400) = ? 5. From — 8 a take —2a. 6. From —2a take 8 a. 7. From — 2 a take — 8 a. 8. From 2 a take — 8 a. 9. From 3 x +14 take as +10. 3a; + 14 - a? -10 10. From 5a;— 8 take— 3a;— 9. 11. From a;— 28 take 5 a,*— 37. 12. From 7a;+16 take 9a;— 4. 13. From 6 x take 2 x — 5. 14. From 8 x take 9 x + 3. 15. From 3 a; + 2 a — 5 take a; — a — 9. 16. From ly — 2z + b take — 8y + 66 — 2. 17. From c — d + e take c + d —f. 543. Written Exercises. 1. From 8 a take 2 a. 8a - 2a Ans. 6a 2. From 2 a take 8 a. 2a - 8a -4ns. - 6a 3. From - - 8 a take 2 a. - 8a - 2a Ans. -10a 4. From 8 a take — 2 a. 8a + 2a Ans. 10 a Algebraic Equations. 435 REMOVING PARENTHESES. 544. Written Exercises. 1. From 6 x + 15 y take 4 x + 10 y. We may write the above in a shorter way, thus : 6x + 15y-(4x + 10 y). The minus sign before the parenthesis shows that the quantity within the parenthesis is to be subtracted. What sign is before 10 y ? What sign is understood within the parenthesis before 4 x ? In subtraction, what is done with the signs of the subtrahend? If the whole expression is written without using the parenthesis, what must be done with the signs of the quantities within the parenthesis ? a — (b — c) may be written a — b + c. Why ? a + (6 — c) may be written a + b — c. Why ? When removing a parenthesis preceded by a minus sign, change the signs of all quantities within the parenthesis. 545. Written Exercises. Write the following without parentheses : 1. 57 + (33 - 16) = 74. 4. (17 - 8) - (16 - 14) = 7. 2. 92 -(63 + 25) =4. 5. 75 + 4 x (15 - 10) = 95. 3. (43 -10) + (24 -5) = 52. 6. 75 -4 x (15- 10) = 55 7. 4 x + 5 y + (2 x — 6 y) = 6 x — y. 8. 4z + 5?/— (2ic + 6?/) = 2a; — y. 9. 4:X — 5y — (x — 6y) = Sx-{-y. 10. 4# — 5?/ — (— ic+ 6?/) = 5-120 = | + 10. 22. a? -20 = (1 + 15^4 23. a + | + | = 19. 24. 9(8a + l)-4 = 4(9a; + 5)+3. 25. 2 a; + 3 = — 549. Written Problems. 1. A certain number is multiplied by 3f; 7 is subtracted from the product ; the remainder is divided by 16, giving a quotient of 3. What is the number ? 2. Three-eighths of what number is 60 less than the number itself ? 3. Four persons are of the same age. If the first were \ of his age older, the second \ of his age older, the third \ of his age older, and the fourth \ of his age older, the sum of their ages would be 99 years. What is the age of each ? 4. A man spends \ of his earnings on board and lodging, ■§- on clothing and repairs, and \ on sundries. At the end of the year he has $ 280 left. What are his yearly earnings ? 3 = ? + | + | + 280. 2i o 5 5. A boy gave \ of his marbles to one companion, and \ of them to another. He then bought \ as many as he origi- nally had, and had 4 marbles more than he had at first. How many did he have at first ? 6. A father's age and a son's age added together amount to 138 years. Twelve years ago the father was twice as old as the son. How old is each now ? Let x = son's age 12 years ago. 2 x = father's age then. Algebraic Equations. 439 7. John has 80 cents, and William has 60 cents. How many cents should William give John so that the latter might have 2\ times as much money as the former ? After William gives John x cents, the former has (60 — x) cents, and the latter has (80 -f x) cents. 8. In how many years will a man, now 25, be double the age of his 11-year-old brother ? Let x = number of years. 25 + x and 11 + x = ages after x years. 9. A man has a cask of 60 gallons' capacity. He draws off one-fourth of its contents, and then fills it. If it takes 24 gallons to fill it, how many gallons did the cask originally contain ? 10. A number is divided by 3, and 40 is subtracted from the quotient, leaving a remainder of 104. What is the number ? 11. The difference between two numbers is 430. When the greater is divided by the less, the quotient is 4, and the remainder is 76. What are the numbers ? Let x = less. EH*L r = 4 + It less less 12. A person pays $103 with 29 $2 and $5 bills. How many are there of each denomination ? 13. A father is 30 years older than his daughter. In 4 years, his age will be four times her age. What are their present ages ? x and x + 30 = present ages, x + 4 and x + 34 = ages 4 years later. 14. The product of two numbers is 180. If the smaller number be increased by 3, the product of the two numbers will be 225. What are the numbers ? smaller = x ; — = greater. x 15. A man's wages are $ 1 per day more than his son's. For 33 days' work, the father receives $ 12 more than the son earns in 40 days. Find the wages of each. 440 Chapter Seven. TWO UNKNOWN QUANTITIES. 550. Preliminary Problems. 1. I paid a dollar for two 25^ balls and five bats. How much did I pay apiece for the latter ? 2. When three times one number is added to five times another, the sum is 84. If the second number is 12, what is the first number ? 3. A girl paid 75^ for £ pound of tea and 2\ pounds of coffee. The coffee cost 20 ^ per pound. What was the price of the tea per pound ? 4. A man sold pigs at $5 each and lambs at $8 each, receiving $42. He sold 4 lambs. How many pigs did he sell? 5 . Four times a father's age added to twice his daughter's age amounts to 180 years. The girl is 10 years old. What is the father's age ? 6. Eight peaches and seven pears cost 44^. The peaches cost 2^ each. What is the cost of a pear? 7. Two pieces of cloth and eleven pieces of silk contain 152 yards. There are 10 yards in each piece of cloth. How many yards in each piece of silk ? 8. Two-thirds of a yard of linen and three-fourths of a yard of lace cost 40^. The price of the lace is 32^ a yard. Find the price of the linen. 9. Three and one-half times one number added to four and one-third times a second number equals 60. The second number is 9. What is the first number ? 551. Written Exercises. Find the value of the unknown quantity : 1. 8 x + ly = 44. When a = 2, find the value of y, 2. 3 y + 5 z m 34. Find the value of z ; y = 3. 3. 2a + ll3 = 152. a; = 10;2 = ?. 4. 14a + 7y = 98. x = 3%-,y=?. Algebraic Equations. 441 5. !'*+ f*x=40. 2 = 32. 6. 9x- 25y = 8. x = 12. 7 . 3Jy + 4i*==eO. z = 9. 8. 16a>-19z = 49. z = 5. 9. 7y- 3* = 18. 2/ = 6f 10. 32x + 50?/ =2600. 2/ =20. 552. Written Problems. 1. The cost of 3 apples and 2 peaches is 7 cents. The cost of 2 apples and 2 peaches is 6 cents. Subtracting the second lot of fruit from the first lot we have 1 apple. Subtracting the price of the second lot from the price of the first lot we have 1 cent. 1 apple costs 1 cent. If equals are subtracted from equals, the remainders are equal. 2. A boy gave 2S$ for 3 lemons and 8 oranges, another boy paid 11$ for 3 lemons and 4 oranges. How much did the lemons cost apiece ? x = cost of lemons, 3 x + 8 y = 25 (1) y = cost of oranges, 3 x + 4 y = 17 (2) Subtracting (2) from (1), 4y= 8 The oranges cost 2f each, y = 2. How much apiece was paid for the lemons ? 3. If 3 coats and 14 vests cost $ 78, and 2 coats and 14 vests, at the same rate, cost $66 } how much does 1 coat cost ? What is the price of a vest ? 4. Given 4z + ly = 53, (1) 2x + 32/ = 25, ' (2) to find the value of y. First multiply (2) by 2, making it 4 re + 6 x = 50. Why ? 5. What is the value of x in equation (1) in above ex- ample, when the value found for y is substituted therein ? Substitute the same value for y in equation (2) and find the value of x. 442 Chapter Seven. 553. Written Exercises. Find the values of x and y in the following equations : 1. x + 2/ = 15, 3. 2x + 3y = 18, 2x + 3 y = 38. 4# + 3y == 24. 2. 2z + 2y = 30, 4. 2a; + 3?/ = 40, x + 32/ = 27. 3z + 2?/ = 35. Multiply first equation by 3, 6 x + 9 y = 120. Multiply second equation by 2, 6 a; + 4 y = 70. 5. 7 a? + 5 ?/ = 82, 6. 5 a -f- 9 y = 14, 2 * + 3 ?/ = 36. 9*4 5 ?/ =14. 7. 3a> + 53/ = 17, 8. 2x-3y = l$, 8 8. + 2 2/ = 17. 3z + 52/ = 65. Given ; ft ( _ . * ' \ To find values of x and y. (2) 7 # — 4 2/ = 22. J * Multiply (1) by 7, 7 x + 21 y = 322 (2) Ix- 4y = 22 Subtract. 25 y = 300 y= 12 Substituting this value of y in (1), we have x + 36 = 46, a; = 46 - 36 = 10. Arts, x = 10, y = 12. 9. a; -J- y = 18, Add or subtract. a-y- 4. 10. 4 a; + 3 # = 17, (1) Multiply (2) by 2 and subtract. 2a- y= I- (2) 11. 3 a; + 4 y = 48, Add. a? — 4 y = 0. 12. 3 a; + 5 y = 13, (1) Multiply (1) by 7 and (2) by 3. 7x + 3y = 13. (2) Subtract. Algebraic Equations. 443 13. 4 x + 5y = 32, Add. 6a; — 5y = — 2. 14. 3 4 + 4 2/ = 3, (1) Multiply (2) by 2. Add. 12 x -2 ?/ = 3. (2) 15. 5 a; = 6 2/ + 5, Transpose. 3 x = 5 y — 4. 16. 3z + 5y+ 8 = 0, 17 y — 2x=8x — l, 2 as - 2/ - 12 = 0. 2y — 4=x = y + x-+ 9. 18. 5x+ 7y = 55, (1) 9 x + 18 y = 126. (2) Divide (2) by 9 getting x + 2 y = 14. C3) Then multiply (3) by 5. 19. S + ?J? = 17. Clear of fractions. 4 3 5a; 5j/ = 20 4 8 20. £a?-f£y = 42, 24. 4^a; + 3|2/ = 67, i*-Hy=F 17* 7^a;-5i2/ = 12. 21. 23x-7y= 3a; + 51, 25. 3 (a> + 7) =9(2/ -9), ll2/ = 15a; + 2. 4(3 a> -8) = 17 y -155. 22. x -\-y = 100,000, 26. 2(* - 11) -2(2/-9)= 6, fo + S=^°- a? + 9 32 y-S 15 23 - f^I= 5 > »-4 y-l_ 6 3 4 7a;-6_ 2 5y + 3 a;_4 2/-l_i 3 4 28. 2a>4-5*/ + 3 = 6 3a;-42/-2 ' 4a;-7?/4-5_^ a;-22/ + 2 444 Chapter Seven. 554. Written Problems. 1. The sum of two numbers is 37. Twice the first added to three times the second is 96. What are the numbers ? Let x = first number ; y = second number. 2. The difference between two numbers is 28. Five times the first less twice the second is 197. What are the numbers ? x-y = 28; hx-2y- 197. 3. The product of the first of two numbers by 5, added to the product of the second by 3, gives 37. The product of the first by 6, diminished by five times the second, equals 10. Find the numbers. 4. Divide 65 into two parts whose difference shall be 19. Let x and y = parts. Solve also by one unknown quantity. 5. A person pays $103 with 32 bills, some of them $2 bills, the others $ 5 bills. How many of each does he use ? 6. For 25 head of pigs and sheep, a farmer received $ 145. How many of each did he sell, if he sold the former at $7 each, the latter at $5 each ? 7. 10 oranges and 4 peaches cost 38^; 6 oranges and 7 peaches cost 32 ^. Find the cost of an orange. Of a peach. 8. 5 pounds of tea and 3 pounds of coffee cost $3.75; 8 pounds of tea and 1 pound of coffee cost $ 5.05. What is each worth per pound ? 9. A farmer buys a certain number of horses at $125 each and a certain number of cows at $ 40 each. They cost together $ 740. If he had bought half as many horses and twice as many cows they would have cost $730. How many of each did he buy ? 10. A man paid 75^ for 2 pounds of raisins and 3 pounds of cheese. 5 pounds of raisins and 2 pounds of cheese at the same prices would have cost 94^. What did each cost per pound ? Algebraic Equations. 445 11. The sum of two numbers is 19. The sum of the second number and ten times the first, minus the sum of the first and ten times the second, equals 45. What are the numbers ? 12. Reduce ^ to an equivalent fraction, the sum of whose numerator and denominator shall be 126. x = numerator ; y = denominator. * = ±.;x + y = 126. y 13 13. What fraction equivalent to -^ has 147 for the dif- ference between its numerator and denominator ? x - y = - 147. Why ? 14. 10 pounds of coffee at 30^ per pound are mixed with x pounds of coffee at 25^ per pound. What is x equal to, when the mixture is worth 26^ per pound ? 25x + (10 x 30) = 26 (10 + x). 15. A grocer mixes green tea costing 60^ per pound with black tea costing 40^ per pound. He uses 100 pounds in all, and the mixed tea costs him 48 ^ per pound. How many pounds of each does he use ? Let x = number of pounds of black tea ; y = number of green. Then x + y — number of pounds of mixed tea. x + y = 100 ; 40 x + 60 y = 48 (x + y). THREE UNKNOWN QUANTITIES. 555. 1. Given the following : 3x + 2y- 2 = 12, (a) 5 x _ 4 y + 3 z = 16, (6) 2 x + 3 y + 2 z = 35, (c) to find the values of x, y, and z. 446 Chapter Seven. (a) multiplied by 5, 15 x + 10 y - 5 * = 60 (6) multiplied by 3, 15 x - 12 y + 9 z - 48 Subtract, 22 y - 14 z = 12 (d) an equation containing only two unknown quantities. (6) multiplied by 2, 10 x - 8 y + 6 z = 32 (c) multiplied by 5, 10 a + 15 y + 10 z = 175 Subtract, - 23 y - 4 3 = - 143 («) an equation containing only two unknown quantities. Compare the two equations (d) and (e), which contain the same two unknown quantities. (d) multiplied by 2, 44 y - 28 z — 24 (e) multiplied by 7, — 161 y - 28 z = - 1001 Subtract, 205 y m 1025 y m 5 Substituting this value of y in (. 19. 20ax 2 + 15a 2 ar } -20a 3 a; 4 . 12. 4z 4 +6ar 5 +8z 2 +10x+12. 2 0. a¥ + aV. 13. ^a^-gacr'+eac 3 . 21. 6 a? + 1 a* + 2 a«. 14. 3a6 2 + 2a 2 6 + 2a 3 . 22. a 2 x A + a 3 ^ 3 + a 4 s 4 . 15. 3a 2 6 + 6a& 2 -15a& 8 . 23. 12 m 3 n -f 5 m 2 n 2 + 15 ny. 16. #yz + xyz 2 . 24. a 7 — a 5 6 2 -f a 4 ^. 17. 9 m% - 27 m s n 2 y. 25. 70 a 7 + 60 x 6 - 50 a 5 . 582. The square of x -f- y is x 2 -f- 2 xy -f y\ Note that x 2 and y 2 are the squares of x and y, respectively, and that 2 scy is twice the product of x and y. The square of the sum of two quantities is equal to the square of the first, plus twice the product of the first and the second, plus the square of the second. Any expression in the form of x 2 -f 2 xy -f- y 2 is composed of two equal factors. a 2 + 2a& + & 2 = (a + 6)(a + b) or (a + &)*. Algebraic Equations. 461 583 1 Factor: 1. c 2 + 2cd + d?. 14. c 2 d 2 46cdm49m ! . 2. m 2 4 2 m + 1. 15. 4a 2 + 12a + 9. 3. 4 + 4w + m; 2 . 16. 9a 2 4- 12 ab 4 4 6*. 4. a¥ 4 2 axy 4 y 2 . 17. 4 a 2 4- 4 ac 4- c 2 . 5. r 2 + 2 rs£ 4 s 2 * 2 . 18 a*4-2a 2 &4& 2 . 6. e 2 + 6e+9. 19. a 2 4 2 abx 4 &W 7. x 2 + 8 a; 4 16. 20. a 2 6 2 4 2 afcca" 4 c¥. 8. 4 6 2 4 46d4d 2 . 21. m 2 n 2 4l0mn + 25. 9. a 2 4 4 ay 4 4 y 2 . 22. 96 2 + 30 6c4 25c 2 . 10. a 2 4 4 ayz 4 4 ?/ 2 2 2 . 23. 16 4l6a*/4-4afy 2 . 11. 4a 2 z 2 + 4a6a;4& 2 . 24. x 4 4 2 afy 2 z 4 2/V. 12. M *4-6ttv + 9v*. 25. a 2 6 2 4-12a6cH-36c 2 . 13. a 4 4-2a 2 6 2 4& 4 . 26. 4 ra 2 + 8 mw -|- 4 w 2 . 584. The square of a — b is a 2 — 2 a& 4 6 2 . Compare this form with that of Article 582, and note the difference in signs. Give a general statement for the square of the difference of two quantities. 585. Factor: 1. a 2 - 2 ay + if. 14. x 2 -2x + l. 2. l-2x + x*. 15. 4z 4 -4ar J 4l. 3. m 2 -2mnr + w¥. 16. 4 x 2 — 12 xy 4 9 y 2 . 4. a 2 -4a4 4. 17. 9 y 2 - 12 xy 4 4ar>. 5. 9-6&4& 2 . 18. a 4 - 2 a 2 a 4 ar>. 6. rV - 2 rs£ 4 Z 2 . 19. 9 - 12 b 4 4 6 2 . 7. c*-4 cd4 4d 2 . 20. 4^44 a; 41. 8. 16 b 2 - 8 a; + 1. 21. x 2 + 4 y 2 - A xy. 9. 4 b 2 - 4 6c 4 c 2 . 22. 16 x 2 - 40 a;z 4 25 z*. 10. a 2 ?/ 2 - 4 ayz 4 4 z 2 . 23. b 4 - 2 b 2 cd 2 + c 2 d\ 11. 4 a 2 ?/ 2 -4 ayz + z 2 . 24. 25 z 4 - 30 x 2 4 9. 12. 9a 2 -6ah + h 2 . 25. 25 ar* - 30 ar* 4 9 a. 13. 6 2 c 2 -66cd49d 2 . 26. 503^-60^4183?. 462 Chapter Seven. 586. The product of a + b and a — b is a 2 — 6 2 . Give a general statement for the product of the sum and the difference of two quantities. An expression consists of the difference of the squares of two quantities. What are the factors of the expression ? In factoring an expression first examine it to see if it contains a monomial factor. o 2 — be 2 = b (b 2 — c 2 ). The factors of b 2 - c 2 are 6 + cand6-c. 6 3 - be 2 = b (b + c)(b - c). 12. m 2 -9n 2 . 13. b 5 -9b. 14. 9 m 2 — n 2 p 2 . 15. 9 6 2 -4. 16. 4 c 2 -9^. 17. 6c 2 -4 6d 2 . 18. a A -b 2 . 19. x*-y 2 . 20. xif — a 2 b 2 x. 21. afy 2 -a 2 6 2 . 22. -m 2 + aV. 588. The product of x + 2 and a? + 3 is ar 2 4- 5 a; + 6. Note that the coefficient of the second term of the product is the sum of the second terms of the factors ; 5 = 2 4- 3. Note that the last term of the product is the product of the second terms of the factors ; 6 = 2 times 3. Factor x 2 + 7 x + 12. We must find two numbers whose sum is 7 and whose product is 12. These numbers are 3 and 4. a? + 7 x + 12 = (x + 3) (x + 4). In a similar manner, we find x 2 + 6 x + 5 = (x + 1) (a? + 5). 587. Factor: 1. m 2 — n 2 . 2. 1-m 2 . 3. a^-4. 4. c 2 - ay. 5. 9-v 2 . 6. h 2 - 16. 7. 4 ar* — y 2 . 8. oV — # 2 . 9. a 2 — 4 ?/ 2 . 10. 4 a 2 6 2 — w 2 . 11. aw 2 — 4 a. Algebraic Equations. 463 589. Factor: 1. ^ + 43 + 3. 14. 7* + 10r + 9. 2. m 2 + 6m + 8. 15. s^lls + lS. 3. 6 2 + 7& + 10. \ 16. 24 + 10a + a 2 . 4. c 2 + 7c + 6. 17. ^ + 11^ + 24. 5. a 2 + 8a + 7. 18. 20 + 12^ + ^. 6. a 2 + 9a + 14. 19. x 2 + 12x + 32. 7. y* + 8y + 12. 20. 27 + 12x + x*. 8. d 2 + 10d + 16. 21. a 2 + 14a + 24. 9. 7t 2 + 87i + 15. 22. c* + 20c + 19. 10. a 2 + 9 a; + 18. 23. 2/ 2 + 12?/ + 35. 11. a; 2 + 9a; + 20. 24. ra 2 + 13m + 30. 12. z 2 + 10z + 21. 25. ar' + llaj + SO. 13. w 2 + 12w + 20. 26. / 2 + 10/+9. 590. The product of x — 2 and a; — 3 is ar* — 5 a; + 6. Compare with Article 588 and note the difference in signs. a 2 - 11 a + 10 = (a - 10) (a - 1). 591. Factor: 1. c 2 -7c+12. 9. w 2 -14w + 45. 2. +(3) 3 . 22. a? - 64 y 5 . 6 . &-<*&. 15. l + 27d 3 . 23. a 3 6 3 + = 2 x(a 2 + 3 ar 2 ) (a 2 - 4 ar 2 ), but a 2 - 4 ar> = (a + 2 a?) (a - 2 ar) ; hence 2a 4 a;-2cW- 24rf = 2aj(a 2 + 3« 8 ) (a + 2 a?) (a -2 a). 2. Factor ai 6 — # 6 . Since x e =(x i ) 2 , and ^=(jf) 2 9 x*-tf=(x* + tf)(7*-tf). Factoring the second member of the above equation, ** — f = 0* + V) («* - ^ + 2Z 2 ) (* — 2/) 0* 2 + xy + t/ 2 ) . When in doubt prove your work by either multiplication or division. Algebraic Equations. 467 597. Factor: 1. 7 s?y + 21 xyz 2 . 27. Sb 5 -5b\ 2. ab 2 -2abc + ac 2 . 28. (z + ?/) 2 -l. 3. a 2 t> + 3a&c + 2 6c 2 . 29. a 2 -2 ab + 6 2 -l. 4. a 3 + 2a 2 + a. 30. z 2 -* 5 . 5. 2^-216. 31. 125 x + x\ 6. a?b 2 c? + 6abc + 9. 32. + l -s 2 . 16. ^-16^. 42. a 4 + a 2 + l. 17. a 4 — 16 a 2 6 + 55 b 2 . (Change 42 to same form as 18. o^ + aY- 41 ° 19. z 4 + *y. 43 ' 2/ 2 - 13 2/ + 36. 20. * 4 -*y. 44 ' ^"13 6 2 + 36. 21. fl/-^f-'6« 45 ' *+'*+* 22. ^-5^ 2 + 6^. 46 ' ™ 4 -16. 23. a 3 6 2 + 5a 2 6 3 + 10a6 5 . 47. 16-wiW. 24. (3m) 2 + 2(3m) + l. 48. 16m + 2m 4 . 25. (x + y) 2 + 2(x + y) + l. 49. 16 a -a 4 . 26. (x + y) 2 -2(x + y)z + z 2 . 50. a 6 -64. 468 Chapter Seven. FRACTIONS. 598. Preliminary Exercises. 1. Keduce 9! to its lowest terms. Ans. ^-> xz z Divide the numerator and the denominator by x. 2. Change ^ to an equivalent fraction whose denominator is be. Ans. ^ be Multiply the numerator and the denominator by c. The value of a fraction is not changed when both numerator and denominator are either multiplied or divided by the same quantity. 599. Oral Exercises Eeduce : 1. $?*. 2. 3x 2a& o 7 b h? 7 a 3 21 &W a 3 3a 2 ' ax-\- ay 7. 2ab 2 9 nxy + a; Sab a-\- ab ax-f-x 2 6 12a * b \ 8. a 2 + 2ab 10 2px + 3xy 6 ab 3ab px + xy 600. Sight Exercises. Give answers at sight : , b ? a 16 a 3 1. - = — . 6. 4a = — - — 3 3x ? 2 2 V- ? . ' 3x 3a 2 7. 2/ + *_ ? . 2 a 2a& 2a 2ac 8. 2^- 2 f- ' 3 ~ ? " ? 4 5a*/_ ? . 9. 3 7^ = _J 7 ra 14 ran 3 rat 5. 4a = -. a 10. . . » 2a 2 & + 2a# a + = - Algebraic Equations. 469 601. Written Exercises. , .p , a? + lire + 30 1. Keduce — -*- - 1 x + 5 Divide the numerator by the denominator. Ans. x + 6. a . Keduoe *+i2»+35. x + 5 3. Keduce ^ + 10a; + 20 . Jjm. a + 6 a;-f4 # + 4 1 2c + 3 6. Change x+2 to a fraction whose denominator is x+3. • _j. 2 = ?-i — Multiply the numerator and the denominator by x + 3. 7. a -3 = —^—. 8. a^-ic + l = x + 5 a+1 a f racti 3^ + 23; x — 3 9. Change a; H to a fraction. x-\- 2 x — x + 2 x* + 2x x-3 x + 2 x + 2 x + 2 What may be done with the numerators when the denominator is common 10 . Eednce **-}. 13. -^+ 3aJ 2x-l x+2 x+2 11. x — 1 - = -• 14. - = • z + 2 x + 2 x 2x* + x 3 5? 2 9 12. 7^- + —^ = ' - — 15. 2x x + 2 2x? + 4:X y y* — y 16 . §+•=« + *-« a; 2a; + l 2^ + a; 2^ + a; 470 Chapter Seven. "• [x-l)[x-2j ■' e -' (x-l)(x-2) C | multiplied by f = ? 18 ^±1^^L? = 9. u ( a; + 1 )^- 2 ) ==? * a_i * a;_2 *' . ' («-l)(a + 2) ' 19. By what quantity must a; — 5 be multiplied to give a product of a 2 + z -30? By what number must 7 be multiplied to give a product of 63 ? 1 ? 20. 21. 22. 23. x-5 ^ + 05-30 a ? a;_6 a^_a;-30* a aac-f»q a-l~~? x-2\fx + 5\ = l> x-5j\x + 2j ' 24. 05 + 1 a? + 2x + l x-1 ? 25. x-5 ? s + 1 a^-l 26. a; — 5 , x — 1 9 a; + 3 ' a;-h4 - 27. Add*-*and*-?. a; -}- 1 a— 1 Ans. 2^-7» + 8 as»-l 28. a; — 2 x — 5 _ 9 a; — 1 a;-f 1 i 29. z + 5_ ? a;_3 3^-^-6 30. 27a 8 a?-2_ ? 3CUB-1 Algebraic Equations. 471 PURE QUADRATICS. 602. Given ^±-^ = 3a?2 ~ 66 , to find the value of x. 5 9 Clearing of fractions, 9 z 2 + 54 = 16 z 2 - 330. Transposing and combining, — 6 z 2 = — 384. Dividing by - 6, x 2 = 64. Extracting square root, z = ± 8. Since (—8) x (— 8) = 64, the square root of 64 may be either + 8 or — 8. It is written ± 8, and is read "positive or negative 8." (It is sometimes less correctly called plus or minus 8.) 603. Written Exercises. Find value of x, y, z, etc. : 1. ^-13 = 36. 2. 3/ +25 = 100. 3. 5z 2 -13 = 3z 2 + 37. 4. 5(ar } -fl7)-3ar J +63 = 198. 5. 5(^ + 17) -3(^-21) =198. 6. 2/ 2 + 2 2 / + l- 2 / 2 = 49. 7. (a;-f-l) 2 -ar J =49. 8 i/ 2 + 5 2y 2 -18 _o 8. — 4— 2 ' 9 z + 7 = z-5 _ z _3 z _9* 10 20a; = 30a; x — 1 a; + 1 47 2 Chapter Seven. 11. (a; -3) (a? + 3) = 40. 12. (x + 5)(x + 5)=10x + 26. 13. (x + 4:) 2 =8x + 80. 14. z 2 + 64 = 5z 2 . 15. 3^ + 18 = 21^ + 36. 16. (x-3) 2 -(x-5y = 12. 17. (aj + 7)(aj-9) = (aj-3)(a?-6). 18. 4 a; X 5 +5- a; 19. « + 7 a; — 5 a; a; -3 -9 20. 2/-9_ y — 5 2/ -3 + 7 604. "Written Problems. 1. Find the dimensions of a field, the length of which is twice its breadth, its area being 1800 square rods. 2. The surface of the six equal faces of a cube contains 96 square inches. Find the length of one edge. 3. One number is four-fifths of another, and their product is 80. What are the numbers ? 4. One-third of a number multiplied by two-fifths of the same number gives a product of 270. Find the number. 5. Thirty per cent of a number multiplied by forty per cent of the same number gives a product of 300. What is the number? 6. Thirty per cent of twenty per cent of a number is 300. What is the number ? Algebraic Equations. 473 7. The base of a right-angled triangle is f as long as the perpendicular, and the area of the triangle is 96 square rods. Find the length of the base. What is the length of the hypotenuse ? 8. The base of a right-angled triangle measures x yards, 3 x the perpendicular measures — yards. What is the length of the hypotenuse ? If the hypotenuse measures 15 yards, find the length of the base. 9. The base of a right-angled triangle measures x feet, the hypotenuse measures (x-\- 9) feet, the perpendicular measures 15 feet. What is the length of the base ? 10. The difference between the squares of two consecutive numbers is 49. What are the numbers ? 11. The difference between two numbers is 6. The sum of their squares is 146. What are the numbers ? Let x — 3 = smaller number, and x + 3 = greater number. AFFECTED QUADRATICS. 605. Preliminary Exercises. (x + 1 ) (x + 1 ) = z? + 2 x + 1 . Compare with Article 582. 0-l)(a;-l)=a; 2 -2a; + l. Compare with Article 584. (a + 6) 2 =a 2 + 2a& + 6 2 . (m — n) 2 =m 2 — 2 mn -f- n 2 . (10 + 5) 2 = 10 2 + 2 x 10 x 5 + 5 2 . (10-3) 2 = 10 2 -2xl0x3 + 3 2 . 474 Chapter Seven. 606. Oral Exercises. Square : 1. 3J + 3. 4. 3J + 10. 7. 30 — 1. 10. x-y. 2. *— 7, 5. a-6. 8. 40-1. 11. 80 + 5 3. x — 9. 6. # + y. 9. m + n. 12. 60 — 5. 607. Oral Exercises. Extract the square root of 1. a^ + 6a; + 9. 6. x 2 + 2xy + y 2 . 2. a 2 -14a; + 49. 7. a? - 2 an/ + ?/ 2 . 3. ar>-18a; + 81. 8. a 2 -2ab + b 2 . 4. a^ + 20a; + 100. 9. a 2 - 24 x + 144. 5. a 2 + 2a6 + 6 2 . 10. z 2 + 22 a; + 121. The square of (x + 3) consists of how many terms ? Of how many terms does (x + 4) 2 consist ? (a; + 5) 2 ? 608. Supply term necessary to make a complete square : 1. x* + 6x+? 6. x* + 2x + ? 2. a^-12a; + ? 7. 3^-43;+? 3. 3^-83; + ? 8. « 2 -10a; + ? 4. 3^-163?+? 9. 3^+143; + ? 5. 3^ + 183; + ? 10. x 2 -22a; + ? 609. "Written Exercises. Given x 2 + 6x = 27. What number must be added to the first member of the equation to make it a " complete " square ? If a number is added to one member of an equation, what must be done to the other member to preserve the equality ? Algebraic Equations. 475 610. Extract the square root of both members of the fol- lowing equations, adding to both, where necessary, such a number as will make the first member a complete square. 1. x* + 6x + 9 = 40 + 9. 2. a?—12x + 36 = 28 + 36. Remember that (+ 7) x (+ 7) = 49, and that (- 7) x (- 7) = 49. .-. V49 = + 7 or - 7, written ± 7. 3. ^-8^ + 16 = 20 + 16. 7. »*- 14 a; =15. 4. ar J -16a + 64 = -39 + 64. 8. ar»-22a; = 23. 5. + 30a; = 175. 5. a^-14a; = -13. 13. ar> + 28a; = 29. 6. ^-10a; = 0. 14. x 2 + 22 x = 104. 7. x> + 20x = 125. 15. x 2 -16x = -6±. 8. ar J + 26a; = 56. 16. ar 5 + 36a; = 76. To make the first member a complete square, you added the square of what part of the coefficient of x ? 476 Chapter Seven. 613. Written Exercises. Find values of x : 1. a? + a; = 12, 5. x 2 + 9x = -20. x> + x + $y = 12 + (by. 6. ar J -lla;=-28. 2. a?-3a; = 10, 7. a? + 13x = -42. a?-3a;+(f) 2 =10+(f) 2 . 8. a 2 -15 a; =76. 3. a? + 5a; = -4. 9. a?-17a; = 18. 4. a?-7a; = 8. 10. x 2 + 19 x = - 18. 614. When a? has a coefficient, divide both members by the coefficient. 3 a? + 9 a; = 84. Dividing by 3, x 2 + Sx = 28. Completing the square, x* + 3x + (f)2 = 28 + f = 112 + 9 = 121 t 4 4 Extracting square root, x + f = ± ty. ...ar=¥-f = * = 4; or ~y -* = -¥ = - *• ^4ns. 4 or — 7. 615. Written Exercises. 1. 6a 2 - 6a; = 36. 6. 3a? + 9a; = 54. 2. 9a? + 9a; = 180. 7. 8 a 2 - 72 x = - 160. 3. 7a? + 28a;=147. 8. 7a? + 49a; = 56. 4. 4a?-40a; = -64. 9. 3 x 2 + 21 a; = 54. 5. 83? -16a; =504. 10. 5a? -25a; = -20. 616. Five times nothing = ? Zero multiplied by one million = ? If a;»=5, a;-5 = ? lQ(as - 5) = ? (. T + 5)(a; _ 5) = ? Algebraic Equations. 477 If one of two factors is zero, the product is zero. The converse is also true. If the product of two factors is zero, one of the factors is zero. Given (x - 2)(x - 3) = 0. One of the factors in the above equation is equal to zero. If x - 2 = 0, by transposing we get x = 2. If x - 3 = 0, a; = 3. 617. A quadratic equation may sometimes be readily solved by factoring. 1. x>-5x = -6. 2. x*- 5x = 14. ^-5^ + 6 = 0. x 2 -5x-U = 0. (x - S)(x - 2) = 0. (a; - 7)(x + 2) = 0. x = 3 or 2. x = 7 or — 2. Solve by factoring: 3. a 2 + a- 6 = 0. 8. z 2 - 4z + 7 = 19. 4. a? + 2x-3 = 0. 9. ?/ 2 + 10 = 28 + 3y. 5. 3^-3^ + 2 = 12. 10. ^-2^-24 = 0. 6. y 2 + 7y + 15 = 3. 11. ^-15^ = 16. 7. ar>- 7 a; +20 = 8. 12. 2/ 2 + 19?/ = 20. 618. Written Problems. 1. The sum of two numbers is 12; their product is 32. What are the numbers ? x and 12 — x = numbers. (12 — x) x = product. 2. The base of a rectangle is 60 feet longer than its altitude, x Its area is 2400 square feet. How long is the base ? Area x 2 + 50 X 2400 sq. ft. x+ 50 478 Chapter Seven. 3. The perpendicular of a right-angled tri- angle measures 15 yards more than the base. The hypotenuse is 75 yards. Find the length of the perpendicular. x 2 + (15 + xy = 752. 4. The hypotenuse of a right-angled tri- angle is 1J times as long as the base. The area of the triangle is 150 square yards. How- long is the hypotenuse ? Perpendicular = V(£x) 2 - x 2 ; area = £ base x per- pendicular. 5. The entire surface of a square prism is 170 square feet. Its altitude is 6 feet, and one side of its base is x feet. Find the value of x. 50+2Z 6. A garden 50 feet long, 40 feet wide, has a walk just outside it x feet wide. Find the area of the walk. If the area of the walk is 784 square feet, what is its width ? 7. A field, ABCD, contains 12 acres. Its length is 1J times its breadth. How many rods long is the diagonal BG ? 8. A flag-staff, AB, 50 feet high, was broken off at the point C. The broken part, resting on G, reached the ground D, 30 feet from the base of the staff. Find the length of the part broken off. Algebraic Equations. 479 9. A ladder, CE or DE, placed at a point E, in a street 58 feet wide be- tween the opposite houses, just touches the top of a house, DB, 60 feet high on one side of the street, or the top of a house, CA, 56 feet high on the other side. Find the length of the ladder. DE 2 = 60 2 + (58 - x)' 2 = CE 2 = 56 2 + a?. 10. ABC is a triangle. The side AB measures 13 feet ; the side BC, 4 feet ; AC, 15 feet. Find the altitude BD. BD* AD 2 = BC 2 -CD 2 . DxQ 11. ABCD is a trapezium. AB = 34 feet ; BC = 20 feet ; CD = 40 feet ; DA = 26 feet. The perpendicular BF measures 16 feet. Find the length of the diagonal AC and of the perpen- dicular ED. CHAPTER VIII. GEOMETBY. 619. Vertical Lines. Hang a weight from a fixed point by a string. When the weight stops swinging the string is in a vertical line. What way does the lower end of the string point ? the higher end ? Hold a sheet of ruled paper so that the lines are vertical. 620. Oblique and Horizontal Lines. Hold a pointer so that it points upward but not straight up. It is in an oblique line. Hold a pointer so that it does not point or slant either up or down. It is in a horizontal line. Note. — In representing vertical, horizontal, or oblique lines on the page of a book or a sheet of paper it is assumed that the book or paper is held in an upright position. 621. Oral Exercises. 1. What kind of line is represented by the course of a drop of water running down a roof ? 2. By the course of a falling raindrop when there is no wind? 3. By the course of a falling raindrop when there is a wind? 4. By straws floating on the surface of still water ? Use the object for the four following exercises. 6. How many lines are there in the edges of a cube or a rectangular box ? 480 Exercises in Geometry. 481 6. When the cube is placed on a level table, how many- edges are vertical ? How many are horizontal ? How many are oblique ? 7. Hold the cube so that four edges are horizontal. How many are vertical ? How many are oblique ? 8. Hold the cube so that no edges are horizontal. How many are oblique ? How many are vertical ? 9. A straight line is 3 feet long. What kind of line is it if one end is 4 feet from the floor and the other end is 1 foot from the floor ? 10. If one end of a 3-foot straight line is 4 feet from the floor and the other end is 2 feet from the floor, what kind of line is it ? 11. If each end of a straight line is 5 feet from the floor, what kind of line is it ? 12. If one end of a straight line is 4 feet from the floor and the middle is 4 feet from the floor, what kind of line is it? 13.- A vertical straight line is 5 feet long. The middle is 5 feet from the floor. How far is each end from the floor ? 14. A vertical line is 4 feet long. One end is 5 feet from the floor. How far from the floor is the other end ? Why are there two answers ? 622. Angles. When the ends of two straight lines meet they form an angle. A \ What two lines form the angle ABC in the above figure ? At what point do they meet ? *2? The point B is the vertex of the angle ABC. What is the vertex of an angle ? 482 Chapter Eight. 623. Designation of Angles. The angle formed by the lines ST arid. TU may be called the angle T. It is frequently better to call it the angle STU or UTS, the letter at the vertex being placed between the two others. The use of the three letters is necessary where two or more angles have vertices /^ at the same point, as in the accompanying / ^^ figure, where UX, VX, and WX meet at x ^^__ _ w the point X. 624. Exercises. Draw a horizontal line 3 inches long. Mark a point in this line one inch from the left end. From this point draw a line upward slanting towards the right. Mark each end of each line by a letter. How many angles have you formed ? Designate each of these angles by three letters. Note. — The above exercise may be varied for blackboard drill — draw a vertical line 11 inches long ; mark a point 4 inches from the top ; draw a line to the left slanting downward, etc. How many angles are formed when two lines meet at their ends ? When two lines pass through the same point ? When from a point in one line another line is drawn ? 625. Circular Measure. 60 seconds (") 1 minute. 60 minutes (') 1 degree. 360 degrees (°) 1 circle, or circumference. 626. Exercises. 1. What part of a circumference is 180°? 90°? 60°? 30°? 45°? 36°? 72°? 2. 1° on the circumference of a circle is 5 inches. What is the length of the circumference ? Exercises in Geometry. 483 3. The circumference of a circle is 9000 feet. 1° = ? 1'=? 4. How many degrees are there between the XII and the I on the face of a clock ? between the XII and VI ? between the XII and III ? between the III and VII ? 5. If one degree of the earth's circumference is 69^- miles, find the circumference. 6. Through how many degrees does the minute hand of a clock pass in 1 hour? in \ hour? in 15 minutes? in 5 minutes ? in 10 minutes ? in 1 minute ? in 3 minutes ? 627. Angular Measure. The angle at the centre of a circle has the same number of degrees as the arc between the sides of the angle. Thus, in the following figure the angle AOC has the same number of degrees as the arc ABC The circumference of this circle is divided into 36 equal parts. How many degrees are there in each part ? How many degrees are there in each of the following angles ? AOB, BOC, COD, DOE, EOF, FOG, GO A, AOE, DOF. 484 Chapter Eight. 628. The Protractor. The number of degrees in an angle may be measured by a protractor. D unnnm SEMICIRCULAR PROTRACTOR To measure an angle, XYZ, for instance, produce the lines YX and YZ. Place the point A of the protractor on the vertex (Y) of the angle, and the edge AC on the line YZ produced. Using the lower line of figures, read off from the protractor the number of degrees at the point where the line YX produced cuts the semicircle. In measuring the angle DEF, the line AB D* is placed on EF, the point A on the vertex E. The number of degrees in this case is p ^ read from the upper row of figures. Note. — There is only one point on the protractor where the num- bers of the upper and lower lines of figures are equal. What is the number of degrees at that point ? What kind of angle is measured at that point ? If an angle is acute, would you read its measure by the larger or by the smaller number ? Exercises in Geometry. 485 EXERCISES IN CONSTRUCTION. 629. Note. — In the following exercises, the ruler, the compasses, and the protractor may be used. The drawing should be carefully done with a sharp, hard pencil. 1. Draw an obtuse angle formed by two lines, each one inch long. Draw an acute angle formed by two lines, each six inches long. Which is the larger ? 2. The lines OH and IJ intersect at K, making four right angles. Which arc is longer, 7 8 or cd ? Which con- tains the greater number of degrees? 3. Draw two lines meeting at an angle of 45°. Two lines meeting at an angle of 90°. Two meeting at an angle of 135°. 4. Draw two lines making two angles, one of which measures 60°. How many degrees does the other angle contain ? 5. To a horizontal line draw a line making two equal ad- jacent angles. How many degrees does each angle contain ? Two angles are said to be adjacent when they have one side in common. To a vertical line draw a line making two equal adjacent angles. How many degrees does each angle contain ? To an oblique line draw a line making two equal adjacent angles. How many degrees does each angle contain ? 6. How many degrees are there in a right angle ? 7. To an oblique line draw a line making two unequal adjacent angles. How many degrees are there in the sum of the two angles ? Two angles are said to be supplementary when they are together equal to two right angles. 486 Chapter Eight. •fc 8. How many degrees in the angle T y if 8 contains 75° ? V measures 110°. How many degrees does U measure ? If one of two supplementary angles meas- ures 63£°, how many degrees are there in the other angle ? How many degrees are there in an angle supplementary to one of 47° 45'? 9. Construct angle 5, 60°; angle 4, 50°. Measure angle 3. How many degrees and minutes will there be in angle 5 when 3 contains 49£° and 4 contains 83J° ? When angle 3 contains 36° 30' and angle 5 contains 79° 45', how many degrees and minutes will angle 4 contain ? 10. Erect a perpendicular at each extremity of a hori- zontal line. At each extremity of a vertical line. At each extremity of an oblique line. Note. — A line making a right angle with another line is said to be perpendicular to it. 11. Construct a square upon a horizontal line, oblique line. 12. Draw two lines intersecting at an angle of 100°. Mark in each of the other three angles the number of degrees it con- tains. 13. Draw two lines making an angle (6) of 150°. Construct an adjacent angle (7) containing 80°. How many degrees will angle 8 contain? 14. How many degrees will there be in the sum of five angles having the same vertex ? Upon an Exercises in Geometry. 487 15. Draw five equal angles having a common vertex. 16. Draw six equal angles having a common vertex. Is any angle supplementary to the angle next it ? Why ? Are any of the angles vertical ? Why ? 17. Draw two angles,, one of 65° and the other of 25°. Draw a third angle equal to the sum of both. Draw an angle equal to their difference. 18. Draw an angle equal to the sum of three angles measuring, respectively, 40°, 50°, and 60°. 630. Parallels. Lines which lie in the same plane and which cannot meet, no matter how far produced, are said to be parallel. 19. Using the protractor, draw two or more lines that shall be perpendicular to a horizontal line. Where will they meet ? Draw two or more that shall be perpendicular to a verti- cal line. Where will they meet ? Draw two or more that shall be perpendicular to an oblique line. Where will they meet ? 20. To a horizontal line draw two or more lines running in the same direction, and each making an angle of 35° with the first line. Will the oblique lines meet ? Draw two or more lines running in. the same direction, and each making an angle of 125° with a vertical line. Will the oblique lines meet if produced very far ? Draw two or more lines running in the same direction, and each making an angle of 74° with an oblique line. Will the former lines meet ? 21. Draw two lines making angles of 30° and 60°, respec- tively, with a third line. Will the two former lines meet if produced in either direction ? 488 Chapter Eight. 22. Draw a line, AB, meeting a horizontal line, BO, at an angle of 58°. Draw a third line, DE, parallel to the horizontal line, and cut- ting the oblique line. What angles does it make with the oblique line ? Draw a fourth line, EG, parallel to the oblique line, and cutting both hori- zontal lines. Mark in each of the twelve angles the number of degrees it contains. 23. QR and UV are parallel lines, cut by a line ST. If the angle b measures 50°, how many degrees does a measure ? Find the number of degrees in each of the other six angles. 631. Triangles. 24. From the extremities of the line AB, draw lines that shall make angles of 60° and 40°, respec- tively, with AB. Prolong the lines until they meet at C, forming a triangle. Measure the angle at C. How many degrees does it contain? How many degrees are there in the sum of the three angles of the tri- angle ? 25. Construct a triangle having one angle of 90° and one of 30°. Measure the third angle. How many degrees are there in the sum of the three angles ? 26. Construct a triangle, KLM, making the angles at the base 28° and 120°, respectively. Draw NO, parallel to LM. Exercises in Geometry. 489 Is the angle e equal to any angle of the triangle ? How many degrees does it contain ? Is the angle / equal to any angle of the triangle ? How many degrees does it contain ? How many degrees are there in the sum of the angles e, g, and /? How many degrees are there in the angle g ? 27. How many degrees are there in the three angles of any triangle ? 28. Two angles of a triangle measure 36° and 65°, respec- tively. How many degrees does the third angle contain ? 29. Draw a triangle containing two angles of 50° and 70°, respectively. How many degrees are there in the third angle ? Measure each side, and mark on the side its length. Opposite which angle is found the longest side ? Opposite which, the shortest side ? 30. Draw a triangle having two angles of 75° each. Are any two of its sides equal ? Draw a triangle having two angles of 50° each. Are any of its sides equal ? 31. Draw a triangle having two angles of 60° each. How many degrees does the third angle contain ? Are any of its sides equal ? 32. If a triangle has two of its sides equal, what is true of its angles? 33. If a triangle has three of its sides equal, what is true of its angles? 632. A triangle having all its sides equal, is called an equilateral triangle. A triangle having two equal sides, is called an isosceles triangle. A triangle having all its sides unequal, is called a scalene triangle. 49° Chapter Eight. 34. How does a perpendicular let fall upon the of an isosceles triangle from the opposite angle divide the angle ? How does it divide the base ? How do the angles at the base of an isosceles triangle compare with each other as to size ? The unequal side of an isosceles triangle is called the base. 35. Draw an isosceles triangle having the base a vertical line. An isosceles triangle having the vertex below the base. One having an oblique line for the base. 36. Draw a right-angled isosceles triangle. How many- degrees will there be in each of the other angles ? Draw an obtuse-angled isosceles triangle. 37. How many degrees will there be in each angle of an equilateral triangle ? Draw an equilateral triangle having one side vertical. Draw an equilateral triangle having jy q ^ its vertex below the base. 38. DEF is an isosceles triangle, DF and EF being the equal sides. If the angle 1 measures 50°, how many degrees are there in each of the other five angles, when the line FO bisects the base.? 39. ABC is a right-angled A triangle, the angle at B measur- ing 90°, and the angle at C measuring 30°. If the line AX is so drawn as to make the angle AXB equal to 60°, find the number of degrees in the angles m, n, and p, respectively. Exercises in Geometry. 491 633. Quadrilaterals. A plane figure of four sides is called a quadrilateral. When the opposite sides are parallel, the quadrilateral is called a parallelogram. (Figs. 1 to 8.) A rectangle is a parallelogram all of whose angles are right angles. (Figs. 1 to 4.) When the four sides of a rectangle are equal to each other, it is called a square. (Figs. 1 and 2.) The term oblong is frequently applied to rectangles whose adjacent sides are unequal. (Figs. 3 and 4.) Fig. 1. Fig. 2. Fig. 3. Fig. 4. A rhombus is a parallelogram all of whose sides are equal, but whose angles are oblique. (Figs. 5 and 6.) When the adjacent sides of a parallelogram are unequal and the angles are oblique, it is called a rhomboid. (Figs. 7 and 8.) VA Fig. 5. Fig. 6. Fig. 7. Fig. 8. A trapezoid is a quadrilateral having only two of its sides parallel. (Figs. 9 and 10.) A trapezium is a quadrilateral having no two sides paral- lel. (Figs. 11 and 12.) Fig. 9. Fig. 10. Fig. 11. Fig. 12. 492 Chapter Eight. 634. The altitude of a parallelogram is the perpendicular distance between its base and the side opposite. M G x j; b- IT The altitude of a triangle is the perpendicular distance between the vertex and the base, or between the vertex and base produced. AB is the altitude of MANT; DX is the altitude of DBE-, OYoi OHI. 40. Draw a parallelogram. How many angles does it con- tain? Into how few triangles can you divide a parallelo- gram? How many degrees are there in the sum of the angles of each triangle ? How many degrees are there in the sum of the angles of a parallelogram ? 41. Construct a parallelogram, the adjacent sides of which shall measure 2 inches and 3 inches, respectively, and the angle between them 60°. How long will each of the other two sides be? Measure each of the other angles. How many degrees are there in the sum of the four angles ? 42. Construct a trapezoid having a base of 5 inches, alti- tude 3 inches, the angles at the base measuring 90° and 60°, respectively. Measure the remaining angles, and find the sum of the four angles. How long is each of the remaining sides ? 43. Fold a piece of paper twice at right angles, and cut off the folded corner, making a rhombus when the part cut off is opened out. Can you cut out a rhombus having two angles of 60° each ? A rhombus having two angles of 80° each ? Exercises in Geometry. 493 44. Can you so cut a piece of paper, folded twice at right angles, that the part cut off will be a square ? 45. Draw a rectangle, base 2\ inches, altitude 2 inches. A rhomboid, base 2\ inches, altitude 2 inches. 46. Make, out of paper, a rectangle and a rhomboid, each having the above dimensions, and endeavor to ascertain, by cutting, whether or not they are equal to each other in area. 635. The Circle. 47. Draw a circle. Between two points on the circum- ference draw a line that does not pass through the centre. This line is called a chord. 48. Draw a circle. In it draw .two diameters, a radius, and three chords. Write on each line its name. 49. Draw a part of the circumference of a circle greater than one-half of it. Draw the chord. A part of the circumference is called an arc. 50. Draw an arc less than a semi-circumferenee. Draw a chord. Write the name on each. Can you make a chord that will be longer than the diameter ? 51. Draw two equal circles. In the first draw the chord of an arc of 120°. In the second, the chord of an arc of 240°. What is the ratio between the two chords you have drawn ? 52. In a circle draw a chord equal in length to the radius. How many degrees are there in the arc whose chord has been drawn ? 53. Draw an arc of 72°. To its extremities draw two radii. The part of the surface of a circle enclosed by two radii and the intercepted arc is called a sector. 494 * Chapter Eight. 54. Draw a sector of 60° (a sextant). A sector of 90° (a quadrant). 55. Draw an arc of 120°. Draw the chord. The part of the surface of a circle bounded by an arc and its chord is called a segment. 56. Draw several circles having the same centre, but of unequal radii (concentric circles). 57. Draw two equal circles just touching each other (tan- gent). Draw two unequal circles tangent to each other. Within a large circle draw a smaller one tangent to it. 58. Draw circles of equal radii cutting each other. Draw intersecting circles of unequal radii. 636. Pentagons, Hexagons, Octagons. 59. Divide the circumference of a circle into four equal arcs. Draw the chords, forming an inscribed square. 60. If you wish to inscribe in a circle a figure of five equal sides, into how many equal arcs must the circumference be divided ? How many degrees will each arc contain ? 637. A plane figure bounded by straight lines is called a polygon. A five-sided polygon is called a pentagon ; one of six sides, a hexa- gon; of seven, a heptagon; of eight, an octagon; of nine, a nonagon; of ten, a decagon; etc. A regular polygon is one that is both equilateral and equi- angular. 61. Inscribe a regular pentagon in a circle. Use the protractor. 62. Inscribe in a circle a regular hexagon. A regular octagon. An equilateral triangle. Exercises in Geometry. 495 63. Inscribe in a circle a regular hexagon. Connect the opposite corners by lines passing through the centre of the circle, forming six triangles. How many degrees are there in each of the six angles about the centre of the circle ? In each of the twelve angles at the circumference ? How many degrees are there in the sum of angles 1 and 2 ? Is each of the six triangles scalene, equilateral, or isosceles ? 64. Divide a regular inscribed pentagon into five equal triangles by lines drawn from the centre of the circle. What kind of triangles are formed; isosceles, scalene, or equilateral ? How many degrees are there in each angle at the centre ? In each angle at the circumference? How many degrees are there in the sum of two adjoining angles at the circum- ference ? In each angle of the pentagon ? 65. About a circle circumscribe a square. An equilateral triangle. A regular pentagon. A regular hexagon. A regular octagon. PROBLEMS IN CONSTRUCTION. 638. In drawing the following exercises, only the ruler and the compasses are to be used. Use neither the protractor nor the triangle. 66. Draw a circle, radius an inch and a half. Outside of it, and tangent to it, draw a second circle of an inch radius. How far apart are the centres ? 67. Draw two tangent circles having radii of an inch and a half and an inch, respectively, one within the other. How long is the line joining the centres ? 68. With centres 3 inches apart draw two equal circles tangent to each other. How long is the radius of each ? 49^ Chapter Eight. 69. With centres three inches apart draw two equal circles of 2 inches' radius. Connect the centres. Draw a line joining the two points in which the circles intersect. How does this line divide the line connecting the centres ? Draw radii from each centre to each point of intersection. 70. Construct an isosceles triangle, base 3 inches, equal sides 2 inches. Note. — Use circles or arcs where necessary. 71. Construct an isosceles triangle, base 3£ inches, equal sides 4 inches. Divide it into two equal parts. Do not locate the centre of the base by measurements. 72. On a vertical line construct an isosceles triangle. Without measuring the length of the base draw a perpen- dicular to the centre of the base. 73. Bisect a vertical line. An oblique line. Do not measure the length of the line. 74. Construct an equilateral triangle on a two-inch line. 75. Construct an equilateral triangle on a vertical line. On an oblique line. 76. Cut out two equal right-angled triangles. Put them together in different ways so as to form two different isosceles triangles. 77. Construct a scalene triangle. A triangle having sides measuring 1, 1J, 2 inches, respec- tively. One whose sides measure 2, 2|, and 3 inches, respectively. 78. Can you construct an isosceles triangle whose base measures 4 inches, equal sides 2 inches ? Try to construct a scalene triangle with sides measuring 1, 2, and 3 inches, respectively. Exercises in Geometry. 497 79. Draw a circle. In it draw a chord. Bisect the chord, using as few lines and as short ones as you can. Note. — Do not use the ruler to ascertain the length of the chord before bisecting it. 80. Divide a sector into two equal parts. 81. Draw a circle. Draw a chord. Draw a radius through the centre of the chord. Is the radius perpendicular to the chord ? Why ? 82. Bisect the arc of a circle and its chord. Bisect the arc of a circle without drawing the chord. 83. Draw a perpendicular to the middle point of a hori- zontal line. To the middle point of a vertical line. To the middle point of an oblique line. 84. Draw in a circle two diameters perpendicular to each other. 85. Divide the circumference of a circle into four equal parts. Into eight equal parts. Inscribe a square in a circle. 86. Inscribe a regular octagon in a circle. 87. Connect the opposite vertices of a regular octagon inscribed in a circle by lines passing through the centre of the circle. Lines connecting the opposite vertices of a polygon are called diagonals. 88. Inscribe a square in a circle. Circumscribe a square whose sides shall be perpendicular to the diagonals of the inscribed square. 89. Cut out the circumscribed square and show by folding that it is twice the area of the inscribed square. 498 Chapter Eight. 90. Construct an equilateral triangle on a horizontal line 1 inch long. On the right side as a base, construct a second equilateral triangle. On the left side of the first triangle, construct a third Construct three more, completing the hexagon. 91. Can you circumscribe a circle about the above hexa- gon ? What is the radius of the circle ? 92. Inscribe a regular hexagon in a circle whose radius is 1 \ inch. What is the length of each side of the hexagon ? 93. Inscribe in a circle an equilateral triangle. On each of its three sides construct an equilateral triangle. 94. Construct an arc of 60°. Draw two lines meeting at an angle of 60°. 95. Bisect an arc of 60°. Draw two lines meeting at an angle of 30°. 96. Construct an angle of 60° and an angle of 30°. Draw two lines making an angle equal to the sum of the two angles first constructed. 97. Erect a perpendicular at the end of a horizontal line. At the end of a vertical line. At the end of an oblique line. 98. Construct an angle of 45°. An angle of 22£°. An angle of 135°. An angle of 15°. An angle of 75°. 99. Draw a circle, radius 1 inch. Draw a diameter, and produce it an inch beyond the circumference. At the centre of the circle erect a perpendicular to the diameter. 100. An inch from one end of a 3-inch line, erect a perpen- dicular, using as few and as short lines as possible. 101. Draw a horizontal line. Take a point above the line as a center. Draw an arc that cuts the line in two places. 102. Draw a line. From a point above the line, let fall a perpendicular to the line. Exercises in Geometry. 499 EQUAL TRIANGLES. EQUIVALENT TRIANGLES. 639. Note. — The protractor and the triangle may be used in the following exercises. 1. Draw a rectangle, base 2\ inches, altitude 2 inches. Draw a rhomboid, base 2£ inches, altitude 2 inches. Find the area of each. 2. With a base 2 \ inches, altitude 2 inches, draw (a) A right-angled triangle. (b) An isosceles triangle. (c) One or more acute-angled scalene triangles. (d) One or more obtuse-angled triangles. Calculate the area of each. 3. Can you show, by cutting from paper, that a right- angled triangle having its base and perpendicular 4 inches and 3 inches, respectively, has the same surface as an acute- angled triangle whose base and altitude are 4 inches and 3 inches respectively, and an obtuse-angled triangle whose base and altitude are 4 inches and 3 inches, respectively ? Two triangles that have the same area are called equivalent tri- angles ; those having their corresponding sides and angles equal, each to each, are called equal triangles. 4. Construct a triangle whose sides measure 1J, 2, and 2\ inches, respectively. Construct another triangle having its sides of the same lengths. Are the angles of the second equal to the angles of the first ? Are the triangles equal ? 5. Draw two triangles each of which has two sides measuring 1^ and 3 inches, respectively, and the included angle 60 degrees. Is the third side of one triangle equal to the third side of the other? Are the remaining angles of the first triangle equal to the remaining angles of the second ? 500 Chapter Eight. 6. Construct two triangles with equal bases, and angles at the bases respectively equal. Are the triangles equal ? 7. A person wishing to ascertain the length, AB, of a pond, places a pole at a convenient point, G, visible from A and B. The distance BO is measured, and a pole is set up, on a line with B and G, at D, the distance CD being made equal to BG. A pole is also placed at E, on a line with A and C, the distance CE being made equal to AG. Can you show that the length, AB, of the pond can be ascertained by measuring the distance DE ? CALCULATING HEIGHTS AND DISTANCES. 640. To verify the results obtained by calculation, the pupil should make diagrams, drawing the figures to a convenient scale. (7 1. If AB in a right- angled triangle measures ^ 120 feet, and a perpendicu- ^S lar, vw, erected 10 feet from A measures 5 feet, calcu- late the length of BG. Aw:AB::wv:BC: — w i.e. 10 : 120 : 5: BG. 2. A post 6 feet above ground throws a shadow of 7£ feet How high is a tree whose shadow measures 60 feet ? t^ Exercises in Geometry. 5<» 3. Wishing to ascertain the distance between two houses, R and S, on opposite sides of a stream, I measure a line, SV, at right angles to SR, 200 feet. At T, 90 feet from V, the perpendicular TW measures 60 feet. Re- quired the distance SR. VT:TW::VS:SR 4. Beginning at B, 100 feet from the bank of a rive^ a line, BC, is measured 1200 feet long. At D, distant from C 50 feet, the perpendicular DE is found to measure 90 feet. What is the distance from B to A, a tree on the opposite bank ? How wide is the river ? 5. A boy, whose eye (E) is 4 feet from the ground, can just see the top (A) of a steeple when he stands back 3 feet from a fence (CG) 6 feet high. The distance from the foot of the fence to the centre of the base of the steeple is 177 feet. Find the height of the steeple, AB. CD = ? EH=? ED: CD:: EH: AH. When AH is found, how may you get AB ? 502 Chapter Eight. 6. Wishing to ascertain the distance AB, I measure a line, AD, at right angles to AB, 12 chains ; DE, at right angles to AD, 5 chains ; and find that a line sighted from E to B intersects AD at C, distant from D 3.25 chains. What is the distance from AtoB? Note. —The triangles DCE and ACB are similar. Why ? 7. Wishing to find the height of a tower, //, I set up a pole, cd, 12 feet long above the ground. Another pole, ab, 4J feet above ground, is set up at such a distance that the tops of the two poles and of the tower are in a line. The distance between the poles (ae or db) is 10J feet. The distance from d to the foot of the tower is 195 feet. The width of the tower Qcj) is 30 feet. The similar triangles aec and ahf give us the proportion kij ae :ah : : ec: hf. What is the distance ec? ah = bi=bd+dk+ki fh is found, what must be added to get the height of the tower ? 8. To determine the height of a building, MN, a person attached a straight strip of wood, ab, to a post, OP, in such a manner that sighting from a, he could just see M> ki=\kj. When Exercises in Geometry. 503 the top of the building. He then sighted down from b, and marked on the ground the point R, on a line with ab. PQ was found by measurement to be 4 feet, MP 6 feet, PN 120 feet. Eequired, MN. 9. Wood-choppers, desiring to know the height of a tree before cutting it, sometimes make an isosceles right-angled triangle of wood or paper, and " step off " the distance on level ground from the point at which they find they can just see the top of the tree looking along the hypotenuse of the triangle, the base being parallel to the ground. How high is the tree AB, if ^4(7 is 36 paces of 3 feet each, and the angle AGB is 45° ? 10. B is a point on the bank of a stream due east of A on the other bank. A boy walks due south of A until he reaches a point at which he finds, from his pocket compass, that he is directly southwest of B. If the distance AC measures 119 yards, how wide is the stream ? TABLES LINEAR MEASURE 12 inches (in.) . . 3 feet 5£ yards, or 16| feet 40 rods .... 320 rods .... = 1 foot ft. — 1 yard yd. = 1 rod rd. = 1 furlong fur. = 1 mile mi. 1 mi. 320 rd. = 1760 yd. = 5280 ft. = 63,360 in. A hand, used in measuring the height of horses, = 4 in. A knot, used in measuring distances at sea, = 1.15 mi. A fathom, used in measuring the depth of the sea, Oft. SQUARE MEASURE 144 square inches (sq. in.) . . = 1 square foot . 9 square feet = 1 square yard . 30£ sq. yd., or 272^ sq. ft. . . = 1 square rod . 160 square rods = 1 acre . . . 640 acres . . . . < . . . = 1 square mile . sq. ft. sq. yd. sq. rd. A. sq. mi. 1 A. = 160 sq. rd. = 4840 sq. yd. = 43,560 sq. ft. A Section of land is a square mile. Koofing, flooring, and slating are often estimated by the square, -which contains 100 square feet. SURVEYORS' MEASURE In measuring land, surveyors use a chain (ch.) which contains 100 links (1.) and is 4 rods long. Since the chain isf4 rods long, a square chain contains 16 sq. rd., and 10 sq. ch. = 160 sq. rd., or 1 acre. CUBIC MEASURE 1728 cubic inches (cu. in.) . . = 1 cubic foot 27 cubic feet = 1 cubic yard 128 cubic feet = 1 cord . . 16 cubic feet = 1 cord ft. . 8 cord feet = 1 cord . . cu. ft. cu. yd. cd. cd. ft. cd. Note. — In computing the contents of an enclosing wall, masons and brick-layers regard it as one straight wall whose length is the distance around it on the outside. Corners are thus measured twice. A perch of stone or masonry is 16£ ft. long, 1J ft. thick, and 1 ft. high, and contains 24 1 cu. ft. YB 35889 MEASURES OF CAPACITY Liquid Measure Dry Measure 4 gills = 1 pint . . . pt. 2 pints = 1 quart . . qt. 2 pints sb 1 quart . . . qt. 8 quarts s= 1 peck . . pk. 4 quarts = 1 gallon . . gal. 4 pecks = 1 bushel . . bu. The standard gallon contains 231 cubic inches. The standard bushel contains 2150.42 cubic inches. The capacity of cisterns, reservoirs, etc., is often expressed in barrels (bbl.) of 315 gallons each, or in hogsheads (hhd.) of 63 gallons each. In commerce, these vary in size. AVOIRDUPOIS WEIGHT 16 ounces (oz.) 100 y 2000] 1 pound lb. The long and in weigl 1 bushel of 1 bushel of 1 1 bushel of 1 bushel of 24 gr: 20 pe 12 oul 54884 UNIVERSITY OF CALIFORNIA LIBRARY APOTHECARIES' WEIGHT 60 grains (gr. ) . . . . = 1 dram . . . dr., or 3. 8 drams =1 ounce . . . oz., or %. 12 ounces = 1 pound . . . lb., or lb. One pound Apothecaries' weight = 576C grains. BRITISH OR STERLING MONEY 4 farthings =1 penny . .... A . . . s. . . . £. 12 pence = 1 shilling 20 shillings =1 pound 5 shillings =1 crown. The value of £1 is $4.8665 in United States gold coin. The unit of French money is 1 franc, which is 19.3 cents. The unit of German money is 1 mark, which is 23.85 cents. Ililittil 1 1 ■i 11 i in! 1 Jar '111!