1. Find 2%, or .02, of 400; 3% of 500; 7% of 200. 2. How many are 25 %, or 4, of 36? 121% of 40? 331 % of 60? 12. Of the 20 Hawaiian Islands, 60 % are uninhabitable. How many uninhabitable islands are there in the group? 13. French capitalists have 300 million francs invested in Mexico, of which 33% is in mines. How much of their capital is invested in Mexican mines? 14. Of the 200 toy factories in one district of Germany, 75 % make nothing but metal toys. How many make metal toys only? WRITTEN EXERCISES 332. 1. Find 45% of 185.76; also 37% of 110.08. The percentage equals the base multiplied by the rate. Find: 2. 15% of $4424 3. 90% of $7500 4. 40% of 850 T. 5. 461% of 5280 ft. 6. 125% of 5424 gal. 7. % of 160 cu. in. 8. 16% of 14,046 10. 1831% of 58,254 11. 1621% of 58,464 12. One year when 8400 books were published in the United States, 22% of the books were fiction. How many works of fiction were published in the United States that year ? 13. A man willed 371% of his fortune of $240,000 to a hospital. How much did the hospital receive? 14. Red hematite is an ore containing 70% of iron. How many pounds of iron ore can be obtained from a long ton of red hematite? 15. In Oregon the average amount of standing timber per acre of forest land is 12,200 board feet, of which 66% is red fir, 18% pine, 5% spruce, 5% hemlock, 2% cedar, and 4% other kinds. Find the amount of each per acre. 16. When the commerce of the world for a year amounted to $21,900,000,000, the shares of the chief nations were approximately as represented by the following graphs. Find the value of each nation's share. 17. If 57% of the commerce of the United States was exports, what per cent was imports? What was the value of the imports? of the exports? 333. Finding what per cent one number is of another. EXERCISES 1. What part of 30 is 6? How many hundredths of 30 is 6? What per cent of 30 is 6? 10. An elephant at the park eats 100 lb. of hay daily, a hippopotamus, 50 lb. the smaller? What per cent of the larger amount is 11. If Olive and John used 3 qt. of cream and 2 qt. of milk in making ice cream, what per cent of the mixture was cream? 12. Of the 300 coal mines in operation in India recently, 250 were in the province of Bengal. What per cent were in Bengal? Since the percentage equals the product of the base and the rate (§ 332), the rate equals the percentage divided by the base. 14. Of the 6000 men's clothing establishments in this country, 2500 are in New York and 900 in Illinois. What per cent of the whole number is in each of these states? 15. What per cent of the cocoa from 1000 trees, whose average yield is 13 pounds apiece, is cocoa butter, if the cocoa butter amounts to 910 pounds? 16. Of the 20,000,000 bushels of wheat exported by the United States one year, 9,000,000 bushels went to Great Britain. What per cent of the wheat went to Great Britain? 17. If 150 lb. of "lead," used in a medium grade of lead pencils, consisted of 881⁄2 lb. of graphite and the rest clay, find the per cent of each substance in the mixture. 18. The Kohinoor diamond when first cut weighed 279 carats. It was cut a second time and then weighed 106 carats. Find, to the nearest tenth, its per cent of loss in weight due to the second cutting. 19. The New York State Library contains 572,185 volumes and the Library of Congress 1,344,618 volumes. What per cent, to the nearest tenth, of the number of volumes in the Congressional Library is the number in the New York State Library? 21. From the graphs on page 195 find, to the nearest tenth, what per cent the commerce of each nation was of the commerce of Great Britain and Ireland; also what per cent the commerce of each nation was of the commerce of the United States. 335. Finding a number when a per cent of it is given. 1. If of a number is 20, what is of it? what is of it, or the whole number? 2. If of a number is 81, what is of it? 108 of it? 3. If 12% of a number is 48, what is 1% of it? What is the number? How does the result compare with 48÷.12? 4. If 371%, or, of a number is 33, what is the number? 5. If 83%, or 5, of a number is 35, what is the number? 336. 1. Find the number of which 939.75 is 35%. 2. Find the number of which 50.55 is 621%. SOLUTION 10.11 50.55.621 = 50.55 ÷ } = 30.55 × Test. 621%, or §, of 80.88 = 50.55. 8 = 80.88. Since the percentage equals the product of the base and the rate, the base equals the percentage divided by the rate. |
