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 lb., retailed at 3 cents per lb.? 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 24 yards? 24. How much will be paid for 84 yards of silk at $14 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? (104 – 8) is how much greater than (10 — 81)? To subtract 8 from 10 mentally, we find the difference between 8 and 10, which is 1, and to this add . The answer is 12. 10. 11 – 63 = 4} + 3 = ? Divide without writing products (Art. 385): 1. If 17 horses cost $4,387, what will I pay for 51 at the same rate? 618. Problems consisting of multiplication and division can be sometimes shortened by indicating the operations, and then canceling. To solve the above, we indicate the cost of one horse, and of 51 horses, $4387 17 Since 17 is contained in 51 three times, we cancel both numbers by drawing a line through them, and we write a 3 above the 51. The answer is $4,387 x 3 = $ 13,161. 2. If 15 eggs cost 25 cents, what will 10 dozen cost? 25 x 10 x 12 We indicate price of one egg by dividing by 15. Multiplying this by 10 times 12, we get the price of 10 dozen. In this case, 15 is not contained in any number 2 4 above the line. We divide 15 and 10 by 5, canceling 25 × 10 × 12 them and writing quotients 3 and 2 alongside. 3 is contained in 12 4 times; so we cancel 3 and 12. Our answer now is 25 cents x 4 x 2 = 200 cents, or $2. 13 3 3. Eighteen men can do a piece of work in 26 days. How long will it take 13 men to do the same work? One man will take 26 days × 18. 4. Seventeen barrels of flour, 196 lb. 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 $45 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 9,840 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 doz. pens at 42 cents per gross of 12 doz. ? 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? = ; that is, the product of the numerators is divided by the product of the denominators. NOTE. Cancel when possible. Show by a diagram that 2 × 3 tenths = 3 fifths. |