Cotton-seed oil mills obtain several products from the cotton seed as follows: linters, the short fibers not removed in ordinary ginning, used for spinning purposes or made into batting; hulls, sold for cattle feed; cotton-seed oil, used in cooking, for soap, as salad oil, etc.; and oil cake, or meal, the meat of the seed after the oil is pressed out, used for feeding cattle and for fertilizer. 69. An oil mill that uses 30 tons of cotton seed in a day of 24 hours uses how much per hour? 70. How many days must such a mill run to treat 6300 tons of seed? The quantities and values of the products of one ton of cotton seed in a good year are: 71. Price of linters per pound. 72. Price of hulls per ton. 73. Price of oil per gallon. 74. Price of meal per hundredweight. 75. Value of products from one ton of seed. 76. Profit per ton, the expense being $13.75. 77. If the mill consumes 6300 tons of cotton seed during the year, find the total profit at $3.38 per ton. 78. How many pounds are there in a bale of hulls 1 ft. 2 in. by 1 ft. 6 in. by 1 ft. 8 in., if 50.4 cubic inches make one pound? 79. The oil is pressed out of the hulled seed under a plate whose area is 201 square inches. The total pressure is 351 tons. Express the pressure in pounds per square inch. SIMPLE INTEREST 380. The sum paid for the use of money is called interest. 381. The money for the use of which interest is paid is called the principal. 382. The sum of the principal and the interest is called the amount. 383. Interest is reckoned as a certain per cent of the principal, and the rate of interest is the per cent paid for the use of the principal for one year. 384. In ordinary interest calculations, a month is regarded as 30 days, and a year as 12 months, or 360 days. METHOD BY ALIQUOT PARTS 385. 1. If a man pays $6 for the use of $100 for 1 year, how much must he pay for the use of $100 for 2 yr. ? for 3 yr.? How much must he pay for the use of $100 for 6 months, or of a year? for 2 mo., or of 6 mo. ? for 30 days, or of 2 mo.? for 15 days, or of 30 days? 2. When 6% is paid for the use of the principal for 1 year, what per cent of the principal is paid for its use for 2 yr. ? for 6 mo.? for 2 mo. ? for 6 da. ? 3. Find the interest on $400 at 5% for 1 year; for 3 yr. ; for 6 mo.; for 3 yr. 6 mo. 4. What is the interest at 4% on $600 for 1 year? for 2 months? for 15 days? for 1 yr. 2 mo. 15 da. ? WRITTEN EXERCISES 386. 1. Find the interest on $325 for 3 years at 5%. The interest equals the principal multiplied by the rate, multiplied by the number expressing the time in years. 8. Find the interest on $629 for 1 yr. 8 mo. at 7%. NOTE. It is sufficiently accurate to express final results to the nearest cent and intermediate results to the nearest mill. Find, by aliquot parts, the interest on 9. $5000 for 1 yr. 6 mo. at 3% 10. $5000 for 1 yr. 9 mo. at 4% 11. $3225 from Aug. 1, 1906, to Nov. 1, 1907, at 4 % 12. $4175 from May 1, 1906, to Nov. 1, 1909, at 31 % 13. Find the interest and the amount of $500 for 3 22 da. at 5%. 5 mo. yr. Find, by aliquot parts, the interest and the amount of : 14. $5000 for 1 yr. 3 mo. 3 da. at 6% 15. $5000 for 1 yr. 6 mo. 6 da. at 5% 22. $500,000 for 90 days at 2% 23. $3264.18 for 63 days at 5% 24. $4870.21 for 120 days at 6% 25. $3000 from Oct. 11, 1906, to Jan. 26, 1907, at 5% 26. $5000 from Aug. 16, 1907, to Dec. 28, 1909, at 31% 27. $466.30 from Nov. 12, 1906, to June 30, 1912, at 6% 28. $174.65 from Sept. 27, 1906, to Apr. 16, 1908, at 7% 29. $50,000 from Dec. 6, 1907, to June 4, 1908, at 21% 30. $125,000 from Oct. 22, 1906, to Sept. 11, 1907, at 41% 31. $320,000 from May 26, 1907, to July 15, 1910, at 5% SIX PER CENT METHOD 387. The great bulk of money loaned in the money market is loaned for terms of 90 days, 60 days, or less. For such terms and a rate of 6% the most convenient unit of time is 2 months, or 60 days, of a year. Hence, The interest for 60 days at 6 % is 1% of the principal, found by moving the decimal point two places toward the left. By adding or subtracting parts or multiples of the interest for 60 days, the interest for any term may be found. The following processes illustrate the method of finding the interest at 6% on $5000, for the terms mentioned, from the interest for 60 days: 7 |