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? 6. At three-quarters of a dollar each, how many dolls can be bought for a dollar and a half? $ 1} ÷ $ } = $} ÷ $1 = $} × 1. To divide by To divide by To divide by (examples 1 and 3), we multiply by }. To divide by a fraction, multiply by the divisor inverted. Changing the mixed number to an improper fraction, we have, Divide: 3. 2016 4. 5÷1 5. 8÷11 6. 45÷17 7. 241÷20 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. 1. If base-balls are worth 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 $2 each, 16 balls would cost 16 times $," he might stumble at No. 2. By reading 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 $2 each, I can buy as = many balls as there are $ in $12." The work would be 12 ÷ 12 × . 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 $ each; i.e. $48 for balls at $3 each." 2. Paid $12 for base-balls, at ₫ 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 yard of material to make one 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 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 of a dollar per pound, how much can be bought for 1⁄2 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. price per gallon? 14. of what number is 12? 15. 1 yard and 1 foot of wire cost 16 cents. must be paid for a yard? What is the How much 146. Written Problems. 1. How much does a man earn in a day if he earns 451 dollars in a month of 26 working days? 2. When flour is 54 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 13 dollars. How many boys received a share? 5. Paid 38 dollars for 67 cords of wood. What was the price per cord? 6. How many steps will it take to walk 2640 feet, each step being 21 feet in length? 7. A man put 40 bushels of barley into bags holding 1 bushels. How many bags were required? 8. In 24 acres of land, how many building lots of g of an acre? 9. If of a farm is worth $ 8000, what is § of it worth? 10. The product of two factors is 97; one factor is 35. What is the other? |