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, INTEREST., INTEREST is of two kinds ; Simple and Compound
SIMPLE INTEREST Simp'e Interest is the sum paid by the borrower to the lender for the use of money lent; and is generally at a certain rate per cent. per annum, which in several of the United States is fixed by law at 6 per cent. per annum; that is, 61. for the use of 100l. or 6 dollars for the use of 100 dollars for one year, &c.
Principal, is the sum lent.
RULE. Multiply the principal by the rate per cent. and divide the product by 100; the quotient will be the answer.
EXAMPLES, 1. What is the interest of 391. 118.81d. for one year at 6l. per cent. per annum?
fc. $. d.
Ans. £% 78. Odoti 2. What is the interest of 2561. 10s. 4d. for a year, a * per cent. ? .
Ans: 411 16. Cather
$. What is the interest of 5711. 13s. 91. for one year, al. per cent..
Ans. £54 6s. O d. 4. What is the interest of 21. 12s. 9 d. for a year, at 6l. per cent. ?
Ans. f0 3s. 2d.
FEDERAL MONEY. 5. What is the interest of 468 dols. 45 cts. for one year at 6 per cent. ? Scts.
28110, 70=828, 10cts. 7m. Ans. Here I cut off the two right hand inteyers, which di vide by 100: but to divide federal money by 100, you need only call the dollars so many cents, and the inferior denominations decimals of a cent, and it is done.
Therefore you may multiply the principal by the rate, and place the separatrix in the product, as in inultiplication of federal money, and all the figures at the left uf the separatrix, will be the interest in cents, and the first figure on the right will be mills, anıl the others decimals of a mill, as in the following
EXAMPLES. 6. Required the interest of 155 dols. 25 cts. for a year at 6 per cent. 8 cts.
811, 5088, 11cts. 5m. Ins. 7. What is the interest of 19 dollars 51 cents for one year at 5 per ceat. ? $ cts
ANOTHER METHOD. Write down the given principal in cents, which multia ply by the rate, and divide by 100 as before, and you will. hivoilie in rest for a year, in cents, and decimals of a -.cent, as kollows:
9. Who is the interest of 873, 65 cents for a year, at O per cent. :
Principal :56,5 cents.
Ars. 4+1,90cts.=4+18cts, or $4, 41643. 9m. 10. Required the interest of $85, ficts. for a year, at 7 per cent. l'ents.
Ans. 598, 15 cents,=85,98cts. 13m.
CASE II. To find the simple interest of any sun of money, for any . number of years, and parts of a year.
1st. Find the interest of the given sum for one year.
21. Multiply the interest of one year by thw given number of years, and the product will be the ai..wer for that time.
3.1. If there be parts of a vear, as months and dars, work for the months liv ile aliquot parts of a var. and for the days by the Rule of Thrpe Dirert, or bv alleuin 30 days lů the month, and taking aliquot parts of the same. *
* By allowing the month to be so davy, and linking Aliquot paits thoreof, you will have the inrrrest of ar y crunas y som 31llici.ntly pxact for con.mon use ; but if ine suin be very large, you may say,
As 36 days : is to the interest of one year : : so is the miven number of days : to the interest recuired.
EXAMPLES. 1. What is the interest of 751. 8s. 4d. for 5 years and 2 months, at 6l. per cent. per annum? 6. $. .
f. s. d.
22 12 6 Jn. for 5 years.
0 15 1 do. for 2 months. . 10150 12
623 77 Ans.
2. What is tne interest of 64 dollars 58 cents, for 3 years, 3 months, and ten days at 5 per cent. ?
322,90 Interest for 1 year in certs, per
9. Of 1 dollar for 12 years at 5 per cent. ?
Ans. 60cts. 10. Of 215 dollars S4 cts. for 4 and a half years, ats and a half per cent. ?
Ans. $33, 9icts. 6m. 11. What is the amount of S24 dollars, 61.cents, for 5 . years and 5 months, at 6 per cent. ?
. . Ans. $430, 10cts. 874m. 12. Wiat will 30001. amount to in 12 years and 10 months, at 6 per cent. ?
Ans. 65310. 13. What is the interest of 2571. 58. 1d. for 1 year and 3 quarters, at 4 per cent. ? Ans. £18 Os. 1d. Sqrs.
14. What is the interest of 279 dollars, 87 cents for 2 years and a half, at 7 per cent. per annum
Ans. 848, 97cts. 74m. 15. What will 2791. 135. 8d. amount to in 3 years and a half at 57 per cent. per annum?
Ans. £331 18 6d. 16. What is the amount of 341 dols. 60 cts, for 5 years and 3 quarters, at 7 and a half per cent. per annum ?
Ans. $488, 914cts. 17. What will 730 dols. amount to at 6 per cent. in 5 years, 7 months and 12 days, or of a year ?
Ans. $975, 99cts. 18. What is the interest of 1825l. at 5 per cent. per annum, from March 4th, 1796, to March 29th, 1799, (allowing the year to contain 365 days ) Ans. £250.
Note.—The Rules for Simple Interest serve also to calculate Commission, Brokerage, Insurance, or any thing else estimated at a rate per cent.
COMMISSION, IS an allowance of so much per cent. to a factor or correspondent abroad, for buying and selling goods for his employer.
1. What will the commission of 8431 10s. come to at