Hence, to find the interest of any sum for days, we have the following RULE. Q. How do you proceed first? A. I find what fractional part of a month the days are, and reduce the fraction to its lowest terms. Q. What do you make the multiplier ? A. Half of this fraction. Q. How do you halve the fraction? A. Halve the numerator, or double the denominator Q. After you have multiplied by the fraction, what is to be done with the product, to get the interest? A. Cut off two figures, as before. Mental Exercises. 1 What is the interest of $120 for 15 days? 2. Interest of $60 for 15 days? A. 15 cts. A. 10 cts. 3. Interest of $18 for 20 da.? A. 3 cts. 4. Interest of $120 for 1 da.? A. 4 cts. A. 30 cts. For 10 da.? A. 6 cts. For 10 da.? A. 2 cts. For 2 da.? 5. Interest of $60 for 3 da.? A. 3 cts. For 6 da.? A. 6 cts. Exercises for the Slate. 1. What is the interest of $1200 for 2 da.? $1200 Ans. 40 cts. $600 +2, multiplier. Ans. $2,00 2. What is the interest of $600 for 20 da.? 20 days=38 A. $6. 3. What is the interest of $2400 for 15 da.? 4. What is the interest of $3600 for 10 da.? 5. What is the interest of $726 for 20 da. ? 6. What is the interest of $1200 for 1 da. ?--20. 60. For 4 da. ?-80. For 5 da. ?-1. For 10 da. ?-2. For 25 da. ?-5. A. $16,60. 3. For 20 da. ?-4. For: 7. What is the interest of $120 for 8 yrs. 4 mo. 15 da. ? $120 vrs. 4 mo. 100-250; and 15 da. A mo.÷2; then, 501 6000 30 8. What is the interest of $1200,60 for 1 yr. 10 mo. 24 da.? 1 yr. 10 mo.=22÷2=11 mo.; and 24 da. =. Ans. $60,30 $1200,60 113 Note. When the days are an even rumber, it will oftentimes be found convenient to find what fractional part of a month half the days will be, without nalving the fraction afterwards; thus, for 20 days, take 10 days=8=4, the multiplier. 9. What is the interest of $180 for 29 days? A. 87 cts. 10. What is the amount of $180,60 for 2 yrs. 4 mo. 20 da.? A. $206,486. 11. What is the amount of $36,60 for 2 yrs. 1 mo. 5 da.? A. $41,205. 12. What is the interest of $300 for 1 yr. 6 mo. 15 da. ?2775. For 2 yrs. 6 mo. 15 da. ?-4575. For 3 yrs. 4 mo. 10 da. ?6050. For 4 yrs. 4 mo. 5 da. ?-7825. A. $212,25. 13. What is the interest of $600,50 for 2 yrs. ?-7206. For 1 yr. 8 mo. ?-6005. For 2 yrs. 8 mo. 1 da. ?-9618. For 5 yrs. 7 mo. 12 da. ?-202368. For 8 yrs. 4 mo. 4 da. ?-30065. A. $731,308. 14. What is the interest of $700 for 1 yr. ?-42. For 6 mo? 2275. For 4 mo. ?-14. For 20 da. ?-2333. A. $81,083. 15. What is the amount of $60000 3 da. ?-60030. For 8 da. ?-60080. For 9 da. ?-60090. A. $180200. 16. What is the interest of $60 for 2 mo. 1 da.?-61. For 2 mo 2 da. ?-62. For 2 mo. 3 da. ?-63. A. $1,86. 17. What is the interest of $60 for 2 mo. 7 da. ?-67. For 2 . 8 da. -68. For 2 mo. 12 da. ?-72. A. $2,07. 18. What is the interest of $1200 for 12 yrs. 11 mo. 29 da.? A. $935,80. + aegoing example, although it is as difficult a one as usually occurs, is yone third of the usual numver of figures required by other methods. 1 LXIII. It is evident, that, when the rate is either more or les nan 6 per cent., the interest for the given rate will be a certain part of 6 per cent. ; thus, 5 per cent. will be as much as 6 per cent., 4 per cent. much, 7 per cent. as much, &c. To get, of any number, we multiply by the numerator, and divide by the denominator; and, as the denominator will always be 6, and the numerator the given rate, hence, To find the interest of any sum, when the rate is not 6 per cent., we have the following Q. How do you proceed? RULE. A. Find the interest for 6 per cent. as before. A. Multiply the interest of 6 per cent. by the given rate, and always divide by 6. 1. What is the interest of $600 for 1 yr. 2 mo. and 15 days, at 5 per cent.? 600 4200 150 4350 int. at 6 per cent. 6) 21750 Ans. $ 36,25 int. at 5 per cent. 2. What is the interest of $240 for 2 yrs. 6 mo. at 1 per cent. ?5. At 2 per cent. ?-12. At 4 per cent. ?-24. At 6 per cent.? 36. At 10 per cent. ?-60. At 5 per cent. ?-33. A. $171. 3. What is the interest of $480 for 3 yrs. 2 mo., at 15 per cent.?-228. At 20 per cent. ?-304. At 103 per cent. ?-16340. At 15 per cent. ?-23560. At 7 per cent. ?-10640. A. $1037,40. 4. What is the interest of $600 for 15 mo., at 24 per cent. ?20625. At 33 per cent. ?-28125. A. $48,75. 5. What is the interest of $600 from January 1st to March 1st?-6. From January 15th to May 15th ?-12. From January 15th to September 15th ?-24. A. $42. 6. What is the amount of $500 from March 10th, 1824, to March 10th, 1827?-590. From March 29th, 1820, to Marcb 29th, 18267-680. From March 16th, 1820, to March 16th, 1824 ?620. A. $1890. 7. What is the interest of $60 from June 1st, 1826, to November 1st, 1827?-510. From April 1st, 1825, to August 16th, 1826?-495. From July 4th, 1825, to August 19th, 1828 ?–1125. A. $21,30. 8. What is the interest of $300 from September 5th, 1825, to September 25th, 1826?-1. From August 9th, 1826, to December 24th, 1827 ?-2475. A. $25,75. 9. What is the amount of $180 from October 1st, 1826, to December 1st, 1830? A. $225. ¶ LXIV. A concise and practical Rule for the State of New York, in which the interest is established by law at 7 per cent. It has been remarked, that 7 per cent. is of 6 per cent.; that is, more than 6 per cent.: hence, Q. To find the interest at 7 per cent., what is the RULE ? A. Add of the interest, at 6 per cent. (found as before), to itself; the sum will be the interest at 7 per cent. Note. The interest for any rate per cent. may be found in the same manner, by subtracting, when the given rate is under 6 per cent., and adding, when it is more. 1. What is the interest of $360 for 20 days, at 7 per cent. ? at 7 per 2. What is the interest of $60 for 2 yrs. 4 mo., cent.? A. $9,80. 3. What is the amount of $120,60 for 1 yr. 6 mo. 10 da., at 4. What is the amount of $241,20 for 6 mo. 20 da. ?-25058. For 1 mo. 1 da. ?-242653. For 1 yr. 4 mo. 5 da. ?-263946. For 2 yrs. 6 mo. 25 da. ?-284582. A. $1041,761 +. ¶ LXV. Since 6 per cent. is $6 on $100, that is, 180 of the principal, and 5 per cent. Toʊ, &c., hence, To calculate the interest at any rate per cent., when the time ls 1 year, we proceed as follows: RULE. Multiply by the given rate, and cut off two figures, as before. 1."What is the interest of $220,40 for 1 yr., at 9 per cent? $220,40 9 $19,8360 Ans. 2. What is the interest of $1200,30 for 1 yr., at 12 per cent. ? A. $150,03,7. 3. What is the amount of $80,10 for 1 yr. at 2 per cent. ?82102. At 5 per cent. ?-84105. At 10 per cent.?-8811. At per cent. ?-83704. At 19 per cent. ?-95919. 1 LXVI. COMMISSION. A. $433,94+. Q. When an allowance of se much per cent. is made to a person called either a correspondent, factor, or broker, for buying, or assisting in buying and selling goods for his employer, what is it called? A. Commission. RULE. Q. Since commission, insurance, buying and selling stocks, and loss and gain, are rated at so much per cent., without regard to time, how may all these be calculated? A. Multiply by the rate per cent., and cut off two figures, as in the last rule. 1. What would you demand for selling $400 worth of cotton, for 2 per cent. commission? $400 × 2, and cutting off two figures, $10, commission, Ans. 2. My correspondent informs me that he has purchased goods to the amount of $5000; what will his commission amount to at 2 per cent.? A. $125. 3. What must I be allowed for selling 300 pounds of indigo |