1.9 7 16 $14.49 16+ Ans. days; and since 2 days are of 10 days, we take for 2 days. The interest as found for the several time, added together, gives the interest required. If the rate per cent. had been less than have subtracted the fractional part. Having found the interest for 1 year, and then for 2 years, the interest for 5 months is obtained by first taking of 1 year's interest, for 4 months, and then of this last interest for 1 month. And since 10 days are of 1 month, we take of 1 month's interest for the interest of 10 of the last interest parts of the whole We first find the interest on the given sum at 6 per cent., and then add to this interest the fractional part of itself, denoted by the excess of the rate above 6 per cent. This excess is 1 per cent.; therefore we . add of the interest at 6 per cent. to that interest for the answer. 6 per cent, we should RULE 1.. - First find the interest for one year by multiplying the principal by the rate per cent. expressed decimally; and for two or more years multiply this product by the number of years. Find the interest for months by taking the most convenient fractional part or parts of ONE year's interest. Find the interest for days by taking the most convenient fractional part or parts of ONE month's interest. Or, RULE 2.- Find the interest of the given sum at 6 per cent., and then add to this interest, or subtract from it, such a fractional part of itself as the given rate is greater or less than 6 per cent. NOTE 1. of the interest at 6 per cent. may be taken for that at 1 per cent.;, for that at 1 per cent.;, for that at 2 per cent.;, for that at 3 per cent. From the interest at 6 per cent. may be taken of itself for that at 4 per cent.; of itself for that at 4 per cent.; and of itself for that at 5 per cent. To the interest at 6 per cent. may be added of itself for that at 7 per cent.; of itself for that at 7 per cent.; of itself for that at 8 per cent ; and of itself for that at 9 per cent. If the rate is 12 per cent., the interest at 6 per cent. may be taken twice; if 18 per cent., the interest at 6 per cent. may be taken three times, etc. NOTE 2. - When in this book the rate of interest is not given, 6 per cent. is to be understood. EXAMPLES. 2. What is the interest of $16.75 for 7 months and 17 days, at 7 per cent.? Ans. $0.739. 3. What is the interest of $11.10 from April 17, 1852, to December 7, 1852, at 7 per cent.? Ans. $ 0.496. 4. What is the interest of $12.69, from January 2, 1853, to August 30, 1854, at 7 per cent.? Ans. $1.474. 5. What is the interest of $5000 for 2 years 5 months 26 days, at 7 per cent.? 6. What is the amount of $ 416 for 3 years 16 days, at 7 per cent.? Ans. $504.64. 7. What is the interest of $336 for 15 days, at 5 per cent.? Ans. $0.70. 8. What is the interest of $17869.75 from February 7, 1852, to January 11, 1860, at 5 per cent.? Ans. $7083.3703. 9. What is the interest of $300.50 for 1 year 2 months and 15 days? Ans. $21.786. 10. What is the interest of $ 37 for 29 days, at 5 per cent.? ×11. What is the interest of $ 35.61 from November 11, 1861, to December 15, 1863? Ans. $ 4.474. X12. What is the interest of $ 16.76 from December 17, 1841, to January 17, 1852? Ans. $10.139+ X13. What is the interest of $1728.19 from May 7, 1854, to July 17, 1860, at per cent.? Ans. $26.762. 14. What is the interest of $397.16 for 1 year 6 months and Ans. $32.826. 1 day, at 5 per cent.? 15. What is the amount of $100.25 for 2 months and 29 Ans. $101.241. days, at 4 per cent.? 16. What is the interest of $51.17 for 9 months and 29 days, at 4 per cent.? Ans. $1.699. X17. What is the interest of $42.20 for 1 year and 16 days, at 41 per cent. ? # 18. What is the interest of $16.25 for 2 years, at 3 pet cent.? Ans. $ 0.975. 19. What is the interest of $96.84 from November 27, 1849, to July 3, 1852, at 7 per cent.? Ans. $18.883. 20. What is the interest of $786.97 from October 19, 1857, to August 17, 1861, at 74 per cent.? 21. What is the interest of $71.091 from July 29, 1853, to June 19, 1857, at 12 per cent. ? Ans. $33.175. 22. What is the amount of $369.29 for 2 years 3 months and 1 day, at 9 per cent.? Ans. $444.163. 23. What is the interest of $76.35 for 1 year 8 months and 18 days? Ans. $7.864. 24. What is the interest of $ 47.15 for 1 month and 19 days, at 13 per cent.? Ans. $ 866 25. What is the interest of $36.72 from May 16, 1829, to February 18, 1857, at 7 per cent.? Ans. $71.342. +2 26. What is the interest of $ 35.50 for 3 years 5 months and 20 days, at 7 per cent.? Ans. $8.628. 27. What is the amount of $496.30 for 6 months and 20 days, at 7 per cent. ? 5 Ans. $515.60. 28. What is the interest of $ 691.04 for 1 month 3 days, at per cent.? Ans. $3.167. 29. What is the interest of $ 9750 for 4 months, at 2 per cent. a month? Ans. $780. 30. What is the interest of $9162 for 3 months, at 1 per cent. a month? Ans. $412.29. 31. What is the interest of $1500 for 7 months 20 days, at 10 per cent.? Ans. $95.833. X32. What is the interest of $640.50 for 10 months and 26 days, at 10 per cent. ? Ans. $58.00. 33. What is the interest of $3178 for 15 months and 15 days? 34. If a banker borrow $ 10,000 in Boston at 6 per cent., and let the same in Wisconsin at 7 per cent., how much does he make by the operation in that way in 2 years and 63 months? Ans. $255.555. 356. To reckon interest for any number of days, when 12 months of only 30 days each, or 360 days, are considered a year. Ex. 1. What is the interest of $ 460 for 93 days? We multiply the principal by of the number of days, considered as thousandths; since the interest of $1 at 6 per cent. for 6 days is 1 mill or 1 thousandth of a dollar, (Art. 352,) and for any other number of days, at the same per cent., must be one sixth as many mills or thousandths of a dollar as there are days Principal, To of the principal, SECOND OPERATION. of the interest for 60d. 60 days $460 4.60 Interest for 60d. .23 Ans. $7.13 30 days + 3 days. Interest for 3d. Interest for 93d. 93 days Now, since the interest of any sum at 6 per cent. for 2 months, or 60 days, equals of the principal (Art. 352), of $460 $4.60 will be the interest for 60 days; of the interest for 60 days, or $ 2.30, will be that for 30 days; and of the interest for 30 days, or $ 0.23, will be that for 3 days. The interest for the several parts of the time added together must give the interest for the whole time, or 93 days. RULE. Multiply the principal by the number denoting one sixth of the number of days expressed decimally as thousandths. Or, Divide the principal by 100, and take such a part or parts of the quotient as the given number of days is of 60 days. The result will be the interest at 6 per cent., from which it may be found for any other rate, as in Art. 355. NOTE 1. One sixth of the number of days in any number of months of 30 days each is equal to 5 times the number of months. Thus, one sixth of the number of days in 7 months equals 7 X 5, or 35 days; and one sixth of the number of days in 9 months and 13 days equals (9 × 5) + (13 ÷ 6), or 45 + 21 47 days. = = NOTE 2. It is a common practice among mercantile men, in calculating interest, to consider a year to consist of only 360 days, but the laws of some of the States require 365 days to a year. 360 days are in fact only 368 of a common year, and therefore are less than what perfect accuracy would require. Hence, when the year is considered to be one of 365 days, the interest as found by the rule must be diminished by principal by the number of days, and, if the if the rate be 7 PER CENT., divide by 5214 vide by 7300. of itself; Or, we may multiply the rate be 6 PER CENT., divide by 60833; and if the rate be 5 PER CENT., di EXAMPLES. X 2. What is the interest of $96 for 33 days, at 7 per cent.? Ans. $.616. X3. What is the interest of $320.40 for 63 days, at 5 per cent.? >4. What is the interest of $131.20 for 123 days? Ans. $ 2.803. Ans. $2.689. 5. What is the interest of $ 26.60 for 78 days? 6. What is the interest of $5780 for 153 days, at 10 per cent.? Ans. $245.65. 7. What is the interest of $105.10 for 48 days, at 12 per cent.? Ans. $1.681. 8. What is the interest of $13.62 for 93 days, at 71⁄2 per cent.? 9. What is the interest of $ 4580 for 253 days, at 5 per cent.? Ans. $177.02918. 10. What is the interest of $3140 for 273 days, at 7 per cent.? Ans. $166.6813. 11. What is the interest of $10550 for 243 days, at 8 per cent. ? Ans. $569.70. X12. What is the amount of $ 33.44 for 333 days? Ans. $35.295. 13. What is the amount of $71.60 for 3 months and 18 days? X14. What is the interest of $ 92.96 for 4 months and 3 days, at 7 per cent.? { Ans. $2.223. 15. What is the interest of $144.50 for 144 days, allowing 365 days to the year, at 5 per cent.? Ans. $ 2.85. 16. What is the interest of $761.81 for 165 days, allowing 365 days to the year? Ans. $20.662. 17. What is the interest of $560 for 183 days, allowing 365 days to a year, at 7 per cent.? Ans. $19.65. 18. What is the interest of $ 1960 for 93 days? 19. What is the amount of $1000 for 1 month and 3 days? Ans. $1005.50. 20. What is the amount of $7300 for 18 days, at 6 per cent.? Ans. $7321.90. |