SIMPLE INTEREST. Simple Interest is that which arises from the principal only. CASE 1. When the time is any number of years, and the rate per cent. pounds or dollars only; RULE. Multiply the principal by the rate per cent. and divide the product by 100, the quotient will be the interest for one year; which multiply by the years given. PROOF. By the double rule of three: or, it may be proved or calculated practically thus; for the yearly interest at five per cent. take of the principal, and increase or diminish it by proportional parts thereof for any other rate: As, cent. 3 + 31 4 Subtract For Add From said Interest. To said interest. Then, multiply the yearly interest by the number of years, and take the parts for the odd time. EXAMPLES. I What is the interest of 500l. for one year, at 6 per cent. per annum? Also, at all the other preceding rates? 2 What is the interest of 871 14s 5d. for one year, at 6 per cent. per annum ? answer 51 5s 3d. 3 What is the amount of 1737 175 8d. for a year, at 7 per cent, per annum ? answer 1861 is id. 4 What will a bond for 1767 135 9d. amount to in nine years, at 5 per cent. per annum answer 2561 3s 11da When the principal consists of dollars and cents, multiply by the rate per cent. separate the right hand figure, the others will give the answer in mills. What is the interest of 550dols, 75cts. at 6 and at 8 per cent. for 4 years? D. C. 550, 75 6 33045/0 132180 mills. D. C. 550, 75, 8 44060j0 4 176240 mills. CASE CASE 2. When the rate per cent. is 4, 4, or 4 more than the pounds or dollars given ; RULE. To the product made by the pounds, or dollars, add 4, or of the principal, and divide by 100 for the interest required, EXAMPLES. I What is the interest of 2461 18s. and of 658 dollars 40 cents, for 5 years, at 44 per cent. per annum? gr. 1/52 D. C. 4. 263360 27982/0 5 answer 139,91,0 mills. 52 9 3 answer. 2 Calculate the interest of a bond for 4271 18s 9d. for two years, at 5 per cent. per annuh? facit 491 4s 3d. 3 What sum will 1096! 15s 6d. amount to in 4 years, at 6 per cent. per annum ? CASE 2. answer 1381/ 18s 8d. When the time given is months, weeks or days, less or more than a year. RULE. As the months, weeks, or days in a year, Are to the interest of the given sum for a year; So are the months, weeks, or days in the time given, Or, take aliquot parts of the yearly interest for the given parts of a year. EXAMPLES. What will 300l. amount to in 5 years and 10 months at 44 per cent. per annum? 2 What is the interest of 577 178. 8d. 6 per cent. per annum ? 3 How much is the interest of 150l 4 months, at 6 per cent. per annum ? 4 What is the interest of 1261 12s. per cent. per annum? 5 How much is the amount of 2431 54 per cent? 6 Amount. for three months, at answer 171 4d. 19s. for 3 years and answer 301 3s 9d. for 16 weeks, at 4 answer il 15s od. 175. for 146 days, at answer 2491 9s 2d. 11d. for 1 year, 5 6 What is the interest of 71 35 months, at 25 days, at 6 per cent. per annum ? answer 61 6s 101 7 What is the amount of a bond for 116/ 175 2d. for 6 years, 7 months, and 19 days, at 7 per cent. per annum ? answer 17il 25 78. The interest of any sum, for any time, at 6 per cent. per annum, may also be found by this RULE. RULE. Multiply the principal by half the time in months, and divide by 100. Note I. If there be days, take for them fuch part or parts of the prin cipal as half the days are of 30; deducting from the intereft fo found as many pence as there are threes in the pounds of those parts, excepting the units. 2. If the days exceed 30, bring them into months of 30 days each; deducting as above for the threes in the total. 3. To calculate interest on dollars at 6 per cent. for days, multiply the fum by the number of days, divide by 60; and the quotient will be the answer in cents. 4. For 7 per cent, to the intereft at 6, add one sixth. 8 What is the interest of 8271 18s 10d. for 1 year, 11 months, and 20 days, at 6 per cent. per M. d. d. annum? £. S. d. 827 8 10/ 9 What sum will 674/13s 8d. amount to, in 5 years, #1 months, and 28 days, at 6 per cent. per annum? answer 9171 6s xd. 10 What is the interest of 517 dollars for 30 days, at 6 answer 2,58 per cent. per annum 11 What is the interest of 325 dollars, at 6 per cent. per annum, for 64 days? answer 3,46 12 At 6 per cent. what will the interest be of 100% from Ha the |