14. A commission merchant in New York receives $12000 for the purchase of sugar. He charges 2% commission. What amount is laid out in purchasing sugar, and what is the commission?

15. A factor receives $708.75, and is directed to purchase iron at $45 a ton; he is to receive 5 per cent. on the money paid how much iron can he purchase?

:

16. I forward $2608.625 to a commission merchant in Chicago, requesting him to purchase a quantity of corn; he is to receive 21 per cent. on the purchase: what does his commission amount to, and how much corn can he buy with the remainder, at 56 cents a bushel?

17. My agent at Havana purchased for me a quantity of sugar at 6 cents a pound, for which I allow him a commission of 1 per cent. His commission amounts to $42.66: how many barrels of sugar of 240 pounds each did he purchase, and how much money must I send him to pay for it, including his commission?

18. A merchant in New Orleans received $187.50, to be laid out in the purchase of cotton. After allowing for commission at 2%, freight at 1%, insurance at 3%, and incidental expenses %, what amount was expended in the purchase of cotton, and what was the commission?

19. A commission merchant, in selling a quantity of merchandise for $2785, received a commission of $60: what was the rate of commission?

NOTE. In this example, the base and percentage are given, and the rate is required (Art. 267).

20. A land agent received $175 for selling a house for $6795 what was his rate of commission?

21. A collecting agent received $15 for collecting a debt of $175 what was his rate of commission?

22. A miller received for his toll 5 bushels on every 45 bushels of grain that he ground: what was the rate?

INTEREST.

272. INTEREST is a percentage paid for the use of money. PRINCIPAL, OF BASE, is the money on which interest is paid. RATE of interest is the per cent. paid per year.

AMOUNT is the sum of the principal and interest.
PER ANNUM means by the year.

273. In interest, by general custom, a year is reckoned at 12 months, each having 30 days. The Rate of Interest is generally fixed by law, and is called Legal Interest. Any rate above the legal rate is usury, and is generally forbidden by law.

274. In most of the States, the legal rate is 6 per cent.; in New York, South Carolina and Georgia, it is 7%; and in some of the other States the rate is fixed as high as 10 per

cent.

275. There are five parts in interest: 1st, principal; 2d, rate; 3d, time; 4th, interest; 5th, amount.

CASE I.

276. To find the interest of any principal for one or more years

1. What is the interest of $3920 for 2 years, at 7 per cent.?

ANALYSIS.-In this example, the base is $3920, the rate 7%, and the interest for 1 year is the percentage: this product multiplied by 2, the number of years, gives the interest for 2 years; hence,

Rule.-Multiply the principal

$3920

OPERATION.

.07 rate.

$274.40 int. for 1 year. 2 No. of years.

$548.80 interest.

by the rate, expressed decimally, and the product by the number of years.

Examples.

1. What is the interest of $675 for 1 year, at 6 per cent.? 2. What is the interest of $871.25, for 1 year, at 7%? 3. What is the interest of $535.50, for 7 years, at 6%? 4. What is the interest of $1125.885, for 4 years, at 8% ? 5. What is the interest of $789.74, for 12 years, at 5%? 6. What is the interest of $2500, for 7 years, at 7%? 7. What is the interest of $3153.82, for 2 years, at 4%? 8. What is the amount of $199.48, for 16 years, at 7%? 9. What is the amount of $897.50, for 3 years, at 8% ? 10. What is the interest of $982.35, for 4 years, at 63%? 11. What is the amount of $1500, for 5 years, at 51%? 12. What is the interest of $1914.10, for 6 years, at 31%? 13. What is the interest of $350, for 21 years, at 10% ? 14. What is the amount of $628.50, for 5 years, at 12%? 15. What is the amount of $75.50, for 10 years, at €%? 16. What is the amount of $5040, for 2 years, at 7%?

NOTE.-When there are years and months, and the months are an aliquot part of a year, multiply the interest for 1 year by the years and the months, reduced to the fraction of a year.

17. What is the interest of $119.48, for 2 yrs. 6 mo., at 7% ? 18. What is the interest of $250.60, for 1 yr. 9 mo., at 6% ? 19. What is the interest of $956, for 5 yrs. 4 mo., at 9%? 20. What is the amount of $1575.20, for 3 yrs. 8 mo., at 7% ? 21. What is the amount of $5000, for 2 yrs. 3 mo., at 51%? 22. What is the interest of $1508.20, for 4 yrs. 2 mo., at 10%? 23. What is the interest of $75, for 6 yrs. 10 mo., at 12%? 24. What is the amount of $125, for 5 yrs. 6 mo., at 43%?

272. What is interest? What is the principal or base? What is rate? What is amount? What is the meaning of per annum ?-273. How is a year reckoned, in computing interest? How many days are reckoned in a month? What is legal interest? What is usury?

CASE II.

277. To find the interest on a given principal for any rate and time.

1. What is the interest of $1752.95, at 6 per cent., for 2 yrs. 4 mo. and 29 da. ?

ANALYSIS.-The interest for 1 year is the product of the principal and rate. If the interest for 1 year be divided by 12, the quotient will be the interest for 1 month; if the interest for 1 month be divided by 30, the quotient will be the interest for 1 day.

The interest for 2 years is two times the interest for 1 year; the interest for 4 months, 4 times the interest for 1 month; and the interest for 29 days, 29 times the interest for 1 day.

I. Find the interest for 1 year:

II. Divide this interest by 12, and the quotient will be the interest for 1 month:

III. Divide the interest for 1 month by 30, and the quotient will be the interest for 1 day:

IV. Multiply the interest for 1 year by the number of years, the interest for 1 month by the number of months, and the interest for 1 day by the number of days, and the sum of the products will be the required interest.

274. What are the general rates of legal interest ?-275. How many parts are there in interest? What are they?—276. How do you find the interest of any principal for one or more years?—277. How do you find the interest for any rate and time?

NOTE-This method of computing interest for days, is the one in general use. It supposes the month to contain 30 days, or the year 860 days; whereas, it actually contains 365 days.

30

To find the exact interest for 1 day, we must regard the month as containing 365 days = days; and this is the number by which the interest for one month should be divided, in order to find the exact interest for one day. As the divisor, commonly used, is too small, the interest found for 1 day, is a trifle too large. If entire accuracy is required, the interest for the days must be diminished by its 383 part =

part.

2D METHOD.

278. There is another rule resulting from the last analysis which is regarded as the best general method of computing interest.

Rule.

I. Find the interest for 1 year, and divide it by 12; the quotient will be the interest for 1 month:

II. Multiply the interest for 1 month by the time expressed in months and decimal parts of a month, and the product will be the required interest.

NOTE.-Since a month is reckoned at 30 days, any number of days is reduced to decimals of a month by dividing the number of days by 3.

Examples.

1. What is the interest of $655, for 3 years 7 months and