OPERATION 1. What is the interest of $ 346 for one year ? Ans. $ 20.76. 346 There being two places of deci.06 mals in the multiplier, we point off two in the product. Ans. $ 20.36. There being two places of deci mals in the multiplicand, and two in 4.0 7 22 the multiplier, we point off four 5 places in the product. $20.3 610 3. What is the interest of $ 197 for 1 year ? Ans. $ 11.82. 4. What is the interest of $ 1728 for 3 years ? Ans. $ 311.04. 5. What is the interest of $ 69 for 2 years ? Ans. $ 8.28. 6. What is the interest of $ 1775 for 7 years ? Ans. $ 745.50. 7. What is the interest of $ 987 for 10 years ? Ans. $ 592.20. 8. Required the interest of $ 69.17 for 4 years. Ans. $ 16.60. 9. Required the interest of $ 96.87 for 11 years. Ans. $ 63.93. 10. Required the interest of $ 1.95 for 18 years. Ans. $ 2.10. 11. Required the interest of $ 1789 for 20 years. Ans. $ 2146.80. 12. Required the interest of $ 666.66 for 30 years. Ans. $ 1199.98. 13. What is the amount of $ 98.50 for 5 years ? Ans. $ 128.05. 14. What is the amount of $ 168.13 for 11 years ? Ans. $ 279.09. 15. What is the amount of $ 75.75 for 17 years ? Ans. $ 153.01. 16. Required the amount of $675.50 for 100 years. Ans. $ 4723.50. . II. To find the interest for months, at six per cent. RULE. Multiply the principal by half the number of months, expressed decimally as a per cent. ; that is, for 12 months multiply by .06; for 8 months multiply by .04; for 7 months .035; for 1 month .005, and point for decimals as in the last rule. Nore. It is obvious, that if half the number of months were 12, it would be 1 per cent. a month, that is, half the months will be the per cent. Q. e. d. 1. What is the interest of $ 486 for 10 months ? OPERATION 48 6 principal. .0 5 months decimal of the per cent. $2 4.3 0 Ans. 2. What is the interest of $ 1728 for 18 months ? Ans. $ 155.52. 3. What is the interest of $ 16.87 for 20 months ? Ans. $ 1.68. 4. Required the interest of $ 118.15 for 30 months. Ans. $ 17.72. 5. Required the interest of $ 97.16 for 17 months. Ans. $ 8.25. 6. Required the interest of $ 789.87 for 23 months. Ans. $ 90.83. 17. Required the amount of $ 978.18 for 27 months. Ans. $ 1110.23. 8. Required the amount of $87.96 for 1 month. Ans. $ 88.39. 9. Required the amount of $ 81.81 for 100 months. Ans. $ 122.71. 10. Required the amount of $ 0.87 for 87 months. Ans. $ 1.24. III. To find the interest for any sum for months and days, at 6 per cent. RULE. To one half of the months expressed decimally as in the last rule, annex one sixth of the days. With this multiply the principal, and point of in the product as many decimals as there are in both factors; the first two figures at the right of the separatrix are cents, and the third is mills. Note. If any other per cent. is required, proceed as before, and then divide the product by 6, and multiply the quotient by the rate required. The same result will be obtained if we multiply by the required rate, and divide the product by 6. 1. What is the interest of $ 57.50 for 10 months and 24 Ans. $ 3.105. days? OPERATION. .054 23000 28750 We multiply by .054, because .05 is the rate per cent. for 10 months ; and we annex the 4, because 4 is of the 24 days. 3.1 0 5 0 0 2. What is the interest of $178.75 for 17 months 17 days at 7 per cent. ? Ans. $ 18.31. OPERATION. 178.7 5 .0876 1 25 1 25 143000 14895 6) 1570020 261670 7 18.3 1 690 3. What is the interest of $ 761.75 for 14 months and 18 days ? Ans. $ 55.60. 4. What is the interest of $ 1728.19 for 17 months and 10 days? Ans. $ 149.77. 5. What is the interest of $88.96 for 16 months 6 days ? Ans. $ 7.20. 6. What is the interest of $107.50 for 1 month 29 days? Ans. $ 1.05. 7. What is the interest of $ 87,25 for 20 months 5 days ? Ans. $8.79. 8. What is the interest of $ 73.16 for 19 months 23 days? Ans. $ 7.23. K 9. What is the interest of $ 1.71 for 24 months 2 days ? Ans. $ 0.20. 10. Required the interest of $ 100 for 100 months 1 day. Ans. $ 50.01. 11. Required the interest of three dollars and five cents for 2 months and 2 days. Ans. $ 0.03. IV. When the interest is required on any sum, from a certain day of the month in a year, to a particular day of a month in the same, or in another year, we adopt the following RULE. Find the time by placing the latest date in the upper line, and the earliest date under it. Let the year be placed first ; and the number of months that have elapsed since the year commenced annexed at the right hand, and the day of the month next; then subtract the earlier from the later dale, and the remainder is the time, for which the interest is required. Then proceed as in the last rule. NOTE. Some Arithmeticians prefer reckoning the months by their ordinal number, as in operation 2d. 1. What is the interest of $ 172.50, from Sept. 25, 1840, to July 9, 1842 ? Ans. $ 18.51.5. OPERATION 1st. Y. mo. dan OPERATION 2d. Y. mo. da. 1842 6 9 1 9 14 1842 7 9 1 9 14 $172.50 It will be perceived, that the 1.074 result in finding the time is the 120750 same in operation 2d, as in ope17250 ration 1st. 5750 $ 1 8.5 1 500 2. What is the interest of $ 169.75, from Dec. 10, 1838, to May 5, 1841 ? Ans. $ 24.47. 3. What is the interest of $17.18, from July 29, 1837, to Sept. 1, 1841 ? Ans. $4.21. 4. What is the interest of $ 67.07, from April 7, 1839, to Dec. 11, 1841 ? Ans. $ 10.77. 5. Required the interest of $ 117.75, from Jan. 7, 1839, to Dec. 19, 1841. Ans. $ 20.84. 6. Required the interest of $ 847.15, from Oct. 9, 1839, to Jan. 11, 1843. Ans. $ 165.47. 7. Required the interest of $7.18, from March 1, 1841, to Feb. 11, 1842. Ans. $ 0.40. 8. What is the interest of $ 976.18, from May 29, 1842, to Nov. 25, 1845 ? Ans. $ 204.34. 9. I have John Smith's note for $ 144, dated July 25, 1839; what is due March 9, 1842 ? Ans. $ 166.65. 10. L. Johnson has J. Kimball's note, dated June 4, 1841, for $ 123 ; what is due to Johnson Dec. 7, 1843 ? Ans. $ 141.51. 11. George Cogswell has two notes against J. Doe; the first is for $ 375.83, and is dated Jan. 19, 1840 ; the other is for $ 76.19, dated April 23, 1841 ; what is the amount of both notes Jan. 1, 1842 ? Ans. $ 499.14. 12. What is the interest of $ 68.19, at 7 per cent., from June 5, 1840, to June 11, 1841 ? Ans. $ 4.85. 13. Required the amount of $ 79.15, from Feb. 17, 1839, to Dec. 30, 1842, at 71 per cent. Ans. $ 102.11. 14. What is the amount of $ 89.96, from June 19, 1840, to Dec. 9, 1841, at 84 per cent. Ans. $ 100.88. 15. A. Atwood has J. Smith's note for $ 325, dated June 5, 1839 ; what is due at 74 per cent., July 4, 1841 ? Ans. $374.02. 16. J. Ayer has D. How's note for $1728, dated Dec. 29, 1839; what is the amount Oct. 9, 1842, at 9 per cent. ? Ans. $ 2160.00. 17. What is the interest of $ 976.18, from Jan. 29, 1841, to July 4, 1942, at 12 per cent. ? Ans. $ 167.57. 18. What is the interest of $ 176.17, from June 19, 1839, to Sept. 7, 1843, at 9 per cent. ? Ans. $ 72.42. 19. What is the amount of J. Turner's note for $ 87.25, dated June 1, 1841, to Dec. 17, 1843, at 5 per cent. ? Ans. $ 98.35. 20. What is the amount of $379.78, from Dec. 3, 1808, to August 23, 1847, at 7 per cent. ? Ans. $ 1519.48. |