2. What is the interest of $365 14cts. 6 mills, for three years, 7 months, and 6 days? $78.87 153 interest for 3 years, 7 months, and 6 days; that is $78 87c. 1,53 m. 100 NOTE. Because 7 months are not an even part of a year, take two such numbers as are even parts, and which added together will make 7 (6 and 1)-6 months are of a year, therefore for 6 months, divide the interest of one year by 2; again, 1 month is of 6 months, therefore for 1 month, divide the interest of 6 months by 6.-For the days, because 6 days are of a month, or of 30 days, therefore for 6 days, divide the interest of 1 month by 5. Lastly, add the interest of all the parts of the time together; the sum is the answer. 3. What is the interest of £329 17s. 6d. for 3 years, 7 months, and 12 days, at 5 per cent. per annum? £ S. d. 6 months..... Then 16 9 10 interest of 1 year. £ s. d. 325 17 61 5 3 4. What is the interest of $500 for 3 years, 9 months, and 25 days, at 6 per cent.? Ans. $114.583. 5. What will be the interest of $60-625 for 2 years, 10 months, and 20 days, at 6 per cent.? P Ans. $10.5083+. 6. What is the interest of $124 for 3 months and 10 days, at 6 per cent.? Ans. $2.0663. 7. What is the interest of $215.65 for 5 years, 5 months, and 6 days, at 6 per cent.? Ans. $70-3019. 8. What will be the interest of 75 cents for 4 months, at 6 per cent.? Ans. 015. To find the interest of any sum at 6 per cent. per annum, for any number of months. RULE.-Multiply the principal by half the number of months, and divide the product by 100; the quotient will be the interest for the given time.* EXAMPLES. 1. What is the interest of $225 for 4 months, at 6 per cent.? $225 principal. 2 half the number of months. $4.50 Ans. 2. What is the interest of 1575 dollars for 10 months, at 6 per cent. ? To find the interest of any sum, for any number of days. RULE 1.-Multiply the principal by the given number of days, and that product by the rate, then divide the last product by 365 × 100, and the quotient will be the interest. *The reason of the rule. When the time is months, multiplying by the rate for the time, gives the answer. This rate is found by multiplying the time by the given rate per cent. for a year, and dividing the product by 12; the quotient is the rate required, and is always equal to half the number of months, when the yearly rate is 6 per cent. 204. What is the rule for finding the interest of any sum at 6 per cent. per annum, for any number of months?—-205. What is the reason of the rule? RULE 2.-Multiply the principal by the given number of days, and divide the product by 6083 for 6 per cent. and 7300 for 5 per cent. (the days in which any sum will double at those rates,) and the quotient will be the interest. EXAMPLES. 1. What will be the interest of 320 dollars for 146 days, at 6 per cent.? $ days. rate. 320X46×6=280320; and 365X100=36500. Then 280320÷36500=$7.68 the interest. 2. What is the interest of $225.50 for 292 days, at 6 per cent.? Ans. $10.824. 3. What will be the interest of $225.50 for 292 days, at 6 per cent.? Ans. $10-8243803. 4. What is the interest of 146 dollars for 146 days, at 5 per cent.? Ans. $2.92. To find the interest on bonds, notes of hand, &c. when partial payments have been made, or endorsed on them. RULE 1.--Find the interest of the given sum to the first payment, which either alone, or with any preceding payment, if any, exceeds the interest due at that time, and add that interest to the given sum. RULE 2. From this amount subtract the payment made at that time with the preceding payments, if any, and the remainder will form a new principal; the interest of which find and subtract as of the first sum, and so on till the last payment. NOTE: This mode of computing interest, is established by law in Massachusetts for making up judgments on securities for money draw- » ing interest, and on which partial payments are endorsed. This mode is the most equitable, because the payments are applied to keep down the interest, no part of which, in this method of computation, forms any part of the principal, drawing interest. 206. What are the rules for finding the interest of any sum for any number of days? -207. What is the rule for computing interest upon bonds, notes, &e, upon which partial payments have been made? EXAMPLES. 1. A. gave a note to B. dated Jan. 1, 1929, for $1000, payable on demand, with interest; on which were the following endorsements:- What was the balance due July 1, 1823, interest being computed at 6 per cent.? Calculation. 1000 Principal. 70 Interest to March 1, 1821, 1 yr. 2 months. 1070 Amount. 75 First payment deducted. 995 New principal March 1, 1821. 19-90 Interest to July 1, 1821, 4 months. 1014-90 Amount. 20 00 Second payment deducted. 994-90 New principal July 1, 1821. 79-592 Interest to Nov. 1, 1822, 1 yr. 4 months. 1074-492 Amount. 20.000 Third payment Sept. 1, 1822. 750.000 Fourth payment Nov. 1, 1822. 770.000 Sum of 3d and 4th payments deducted.“ 304-492 New principal Nov. 1, 1822. 310-581 Amount. 100.000 Fifth payment deducted. 210-581 New principal March 1, 1823. 4.212 Interest to July 1, 1823, 4 months. Ans. $214.793 Balance due July 1, 1823. A simple method of operation, is, first to set down against each payment, (as in Ex. I.) the time for which the interest is to be cast: then set down the sums, interest, payments, &c. in columns, as follows: | Principal. |Time. Interest | Payments. Excess. 2. Supposing a note of 867 dollars 33 cents, dated January 6, 1814, upon which the following payments should be made, viz. COMMISSION is a premium, at so much per cent. allowed a person called a correspondent, factor or broker, for assisting merchants, and others, in purchasing and selling goods. RULE.-Multiply the given sum by the rate per cent., and cut off the two right hand figures, as in Simple Interest. 208. What is Commission?--209. What is the rule for calculating commission? |