12. What is the interest of $64.16 for 12 mo. ? 13. What is the interest of $4.67 for 16 yr. 8 mo. ? 14. What is the interest of $35.82 for 2 yr. 9 mo. 10 da. ? 17. What is the interest of $725 for 2 yr. 4 mo. 20 da. ? yr. 4 mo. ? yr. 1 mo.? 18. What is the interest of $768 for 4 yr. 2 mo.? 24. What is the interest of $25.47 for 6 mp. 20 da. ? SOLUTION. 6 mo. 20 da. interest must equal of = 62 mo. = of 20 mo. Hence, the required of the principal, or of $2.547, which is $.849. 25. What is the interest of $57.84 for 20 mo.? 42. What is the interest of $83.60 for 10 mo. ? 43. What is the interest of $95.36 for 3 mo. 10 da.? 44. What is the interest of $57.24 for 2 mo. 15 da.? (d.) Interest for any time whatever can usually be computed easily by dividing the time into some of the above convenient parts, as illustrated in the following solutions. NOTE. In these solutions, letters are used to mark the numbers and indicate to the eye how they have been obtained. Thus, in the first solution, “.04 of a = b= $17.895" means that $17.895 is .04 of $447.38. 45. What is the interest of $447.38 for 8 mo. 10 da.? 46. What is the interest of $873.29 for 2 yr. 7 mo. 20 da. ? 47. What is the interest of $57.20 for 7 mo. 15 da. ? 59. What is the amount of $697 for 6 mo. 26 da.? 111. To compute the Time. (a.) To compute the time during which money has been on interest, i. e. the time between the dates on which interest began and ended, first reckon the number of entire years, then the number of entire calendar months remaining, and then the remaining days. NOTE. This method, although different from that usually given in school arithmetics, is the one adopted by banks and business men, except when the interest is to be computed for some number of days, as 60 days, 90 days, etc., when they count the days from one date to the other. 1. What is the time from April 13, 1853, to Nov. 21, 1856? SOLUTION. From April 13, 1853, to April 13, 1856, is 3 years; from April 13 to Nov. 13 is 7 months; and from Nov. 13 to Nov. 21 is 8 days. the time is 3 yr. 7 mo. 8 da. 2. What is the time from June 23, 1854, to April 8, 1857? Hence, SOLUTION.-From June 23, 1854, to June 23, 1856, is 2 yr.; from June 23, 1856, to March 23, 1857, is 9 months; from March 23 to March 31 (the last day of March) is 8 days, to which adding the 8 days in April gives 16 days. Hence, the time is 2 yr. 9 mo. 16 da. 3. What is the time from Oet. 30, 1855, to March 17, 1857 ? SOLUTION. From Oct. 30, 1855, to Oct. 30, 1856, is 1 year; from Oct. 30, 1856, to Feb. 28, 1857 (the last day of February), is 4 months. There are no days left in February, but there are 17 in March. Hence, the time is 1 yr. 4 mo. 17 da. 4. What is the time from Aug. 18, 1853, to March 12, 1856 ? SOLUTION. From Aug. 18, 1853, to Aug. 18, 1855, is 2 years; from Aug. 18, 1855, to Feb. 18, 1856, is 6 mo.; from Feb. 18, 1856, to Feb. 29, 1856 (February having 29 days in leap-year), is 11 days, to which adding the 12 days in March gives 23 days. Hence, the time is 2 yr. 6 mo. 23 da. 5. What is the time from April 5, 1847, to June 12, 1857? 11. $1000 from Feb. 13, 1852, to June 9, 1856? 14. $924.53 from Oct. 31, 1850, to March 13, 1853? 15. $6000 from March 9, 1855, to March 8, 1856? 16. $6000 from March 9, 1856, to March 8, 1857? 17. $6000 from March 9, 1856, to March 9, 1857 ? 18. $358.70 from April 13, 1857, to Aug. 1, 1857? (c.) What is the amount of — 19. $928.16 from Aug. 23, 1847, to Nov. 30, 1849? 27. Aug. 3, 1847, I borrowed $450; and, Nov. 23, 1847, I borrowed $683.50 more. Jan. 1, 1848, I paid both debts with interest. What was their amount? 28. April 27, 1852, I bought 7 acres of land at $128.36 per acre; Nov. 18, 1852, I sold it at $150.73 per acre. If money was worth 6 per cent per year, how much did I gain by the transaction? 29. Oct. 5, 1857, I bought a lot of grain for $619.27; Nov. 3, I sold a part of it for $328.13; and, Nov. 7, I sold the remainder for $250. Money being worth 6 per cent interest, how much did I lose by the transaction? 112. Interest at various Rates (a.) We may find the interest when the rate is other than 6 per cent, by first computing the interest at 6 per cent, and then getting such part of this as the given rate is of 6 per cent. |