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ANOTHER METHOD. Write down the given principal in cents, which multiply by the rate, and divide by 100 as before, and you will have the interest for a year, in cents, and decimals of a cent, as follows:
9. What is the interest of $73, 65 cents for a year, 6 per cent. Principal 7365 cents.
Ans. 441,90cts.=441 cts. or 84, 41cts. 9in. 10. Required the interest of 885, 45cts. for a year, at 7 per cent. 1
Ans. 598, 15 cents,=85,98cts. 1 fm.
any number of years, and parts of a year.
1st. Find the interest of the given sum for one year.
2d. Multiply the interest of one year by the given number of years, and the product will be the answer for that time.
3d. If there be parts of a year, as months and days, work for the months by the aliquot parts of a year, and for the days by the Rule of Three Direct, or by allowing 30 days to the month, and taking aliquot parts of the
* By allowing the month to be 30 days, and taking aliquot parts thereof, you will have the interest of any ordinary sum sufficiently exact for common use; but if the sum be very large, you may say,
As 365 days : is to the interest of one year : : so is the given number of days : to the interest recuired.
1. What is the interest of 751. 8s. 4d. for 5 years and 2 months, at 6l. per cent. per annum ?
75 8 4
22 12 6 do. for 5 years.
0 15 ) do. for 2 months. 1050 12
£237 7 Ans. 600
2. What is the interest of 64 dollars 58 cents, for 3 years, 5 months, and ten days at 5 per cent. ?
322,90 Interest for 1 year in cents, per
Ans, 1112,19=1112cts. or $11, 12c. 116. 3. What is the interest of 789 dollars for 2 years, at 6 per cent. ?
Ans. $94, 68cts. 4. Of 37 dollars 50 cents, for 4 years, at 6 per
Gent. per annum:
Ans. 900cts. or 89. 5. Of 325 dollars 41 cts. for 3 years and 4 months, at 5 per cent ?
Åns. $54, 23cts. 5m. 6. Of 325l. 126. 3d. for 5 years at 6 per cent. ?
Ans. 697 135. 8d. 7. Of 1741. 10s. 6d. for 3 and a half years at 6 per cent. ?
Ans. £36 138. 8. Of 150. 16s. 8d. for 4 years and 7 months, at 6
Ans. 641 9s. 7d.
per cent. ?
9. Of 1 dollar for 12 years at 5 per cent. ?
Ans. 60cts. 10. Of 215 dollars 54 cts. for 4 and a half years, at 3 and a half per cent. ?
Ans. $33, 9icts. 6m. 11. What is the amount of 324 dollars, 61 cents, for 5 years and 5 monthş, at 6
Ans. 8430, 10cts. 82. m. 12. What will 30001. amount to in 12 years and 10 months, at 6 per cent. ?,
Ans. £,5310. 13. What is the interest of 2571. 5s. 1d. for 1 year and 3 quarters, at 4
Ans. £18 Os. 1d. 3qrs. 14. What is the interest of 279 dollars, 87 cents for 2 years and a half, at 7 per cent. per annum ?
Ans. $48, 97cts. 74m. 15. What will 2791. 135. 8d. amount to in 3 years and a half at 54 per cent. per annum ?
Ans. £331 1s. 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, 91 fcts. 17. What will 730 dols. amount to at 6 per cent. in 5 years, 7 months and 12 days, or is of a year ?
Ans. $975, 99cts. 18. What is the interest of 18251. at 5 per cent. per annum, from March 4th, 1796, to March 29th, 1799, (allowing the year to contain 365 days!)
Ans. £280. 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. 108. come to at 5 per cent. ?
. 6100 442 3s. 6d. 2. Required the commission on 964 dols. 90 cts. at 21
Ans. $21, 71cts. 3. What
may factor demand on 14 per cent. commission, for laying out 3568 dollars ? Ans. 862, 44cts
BROKERAGE,' IS an allowance of so much per cent. to persons assisting merchants, or factors, in purchasing or selling goods.
£. s. d.
1. What is the brokerage of 7501. 8s. 4d. at 68. 8d. per cent. ?
£ 750 8 4 Here I first find the brokerage at I
1 pound per cent. and then for the
given rate, which is of a pound. 7,50 8 4 20
})7 10 1
Ans. 62 10 0 1} 11,00 2. What is the brokerage upon 4125 dols. at for 75 cents per cent. ?
Ans. $30, 93cts. 7 fm. 3. If a broker sells goods to the amount of 5000 dols. what is his demand at 65 cts.
ans $32, 50 ch
4. What may a broker demand, when he sells goods to the value of 5081. 178. 10d. and I allow him 14 per cent ?
Ans. £7 12s. 8d.
INSURANCE IS a premium at so much per cent. allowed to persons and offices, for making good the loss of ships, houses, merchandize, &c. which may happen from storms, fire, &c.
1. What is the insurance of 7251. 8s. 10d. at 12) per cent. ?
Ans. 690 13s. 74d. 2. What is the insurance of an East-India ship and cargo, valued at 123425 dollars, at 15% per cent.?
Ans. $19130, 87 cts. "5m. 3. A man's house estimated at 3500 dollars, was insured against fire, for 14 per cent. a year: what insurance did he annually pay?
Ans. $61, 25cts.
SHORT PRACTICAL RULES,
or months and days.
RULE. 1. If the principal consists of pounds only, cut off the onit figure, and as it then stands it will be the interest for one month, in shillings and decimal parts.
2. If the principal consists of pounds, shillings, &c. reduce it to its decimal value; then remove the decimal point one piace, or figure, further towards the left hand, and as the decimal then stands, it will shew the interest for one month, in shillings, and decimals of a shilling.
1. Required the interest of 541. for seven months and ten days, at 6 per cent.