3. What is the interest of 364 dollars 50 cents for 5 years, at 6 per cent. per annum?

cents 10935,00 Ans. 109 dollars 35 cents.

4. What is the amount of a note for 1260 dollars 50 cents and 5 mills for 3 years, at 7 per cent. per annum ? Ans. 1544 dolls. 11 cts. 8+ ms.

5. What sum will discharge a bond given for 630 dollars 50 cents, on which there is 5 years interest at 8 per cent. per annum? Ans. 882 dolls. 70 cts.

6. What is the difference between the interest of 1274 dollars 64 cents 6 mills for 3 years, at 7 per cent. per an num, and the interest of 3462 dollars 84 cents, for 4 years, at 3 per cent. per annum?

Ans. The latter is 163 dolls. 37 c. 3,85 m. the greater.

7. A gave B his bond for 3422 dolls. 25 cents, to be paid in the following manner, viz. one-third at the end of one year, one-third at the end of two years, and the remainder at the end of three years, with interest from the date, at 6 per cent. per annum; what will be the annual payments, and what the whole amount?

Ans. 1st payment 1209 dolls. 19,5 cts. 2d, 1277 dolls. 64 cts. 3d, 1346 dolls. 8,5 c.; whole amount 3832 d. 92 c.

Case 3.

When the principal is dollars, cents, &c. and the time is years and months, or months only.

RULE.

Multiply by half the number of months in the given time, when the rate is 6 per cent. per annum: but if the rate per cent. be more or less than 6 per cent., multiply the given number of months by the rate, and divide the product by 12; the quotient will be the rate for the time; the principal multiplied by this rate, will give the interest required.

EXAMPLES.

1. What is the interest of 650 dollars for 8 months, at 6 per cent. per annum?

650

4 half the months

cents 2500 Ans. 26 dollars.

2. What is the interest of 860 dollars for 1 year and 6 months, at 6 per cent. per annum?

860

9 half the months

cents 7740 Ans. 77 dolls. 40 cents.

3. What is the interest of 420 dollars for 9 months, at 8 per cent. per annum?

4. What is the amount of a note for 724 dollars, with 18

months interest due thereon, at 4 per cent. per annum ?

Ans. 767 dolls. 44 cts.

5. What is the interest of 240 dollars for 15 months, at 7 per cent. per annum ? Ans. 22 dolls. 50 cts. 6. What is the interest of 1260 dollars for 4 months, at 6 per cent. per annum? Ans. 27 dolls. 30 cts.

Case 4.

When the principal is dollars, cents, &c. and the time is months and days, or days only.

RULE.

Find the interest for the given months by the last case, and take aliquot parts for the days.

Note. In calculation of interest, 30 days make a month.

Or, multiply the given sum when the rate is 6 per cent. by the number of days, and divide the product by 60; the quotient is the interest required.

Note. Though both the foregoing methods are considered sufficiently exact for common business, by merchants and accomptants generally,

yet as this is only allowing 360 days in the year, and not 365, the true time; if, therefore, the principal is large, on which interest is due, and greater exactness is required, then find the interest of the given sum for 1 year, and proceed according to the single rule of three. As 365 days to the interest for one year the given number of days: the an swer. Or by the double rule of three, find the fixed divisors, which for 5 per cent. is 7300, for 6 per cent. is 6083, for 7 per cent. 5214; multiply the principal by the days, and divide by these divisors according to the rate per cent. required.

EXAMPLES.

1. What is the interest of 260 dollars for 5 months and 20 days, at 6 per cent. per annum?

1 month

15 days

5

260
2

5,20 interest for 4 months
1,30

interest for 1 do.

65 interest for 15 days

21,6 interest for 5 do.

7,36,6 Ans. 7 dolls. 36 cts. 6 m.

2. What is the interest of 450 dollars for 36 days, at 6 per cent. per annum?

450

36

2700

1350

6,0) 1620,0

2,70 Ans. 2 dolls. 70 cts.

16200

3. What is the interest of 564 dollars for 44 days, at 6 per cent. per annum?

564

365) 148896 (4,079, Ans. dolls. 07 cts. 9+m.

1460

2896

2555

3410

3285

125

4. What is the interest of 960 dollars for 70 days, at 6 per cent. per annum?

960

70

6083) 67200 (11+ dolls. Ans.

6083

6370

6083

287

5. What is the interest of 12000 dollars for 40 days, at 7 per cent. per annum?

Ans. 92 dolls. 6 cts. 6. What is the interest of 8400 dollars for 20 days, at 5 per cent. per annum?

7.

D. c. days

Ans. 23 dolls.

D.c.m.

517,90 for 84 at 6 per cent. per annum. Ans. 7,15,1

Showing the number of days, from any day in any month, to the same day in any other month through the year.

Feb.

From Ja. | Fb. Mr.|Ap.|Ma.| Ju. |Jly.]Au.] Se.[Oc.|No.|De. To Jan. 365 334|306|275|245|214|184|153|122| 92| 61| 31| 31 365 337 306|276|245|215|184|153 123 92 62 59 28365334|304|273|243|212|181|151|120| 90| 90| 59|31|365|335|304|274|243|212|182|151|121 May 120 89| 1| 30|365|335|304|273|242|212|181|151|

March

April

June

July

Sept.

Oct.

|151|120|92|61|31|365|335|304|273|243|212|182| |181|150|122 91 61 30 365 334303273|242|212| August 212 181153|122 92 61 31 365|334|304|273|243| |243|212|184|153|123||92| 62| 31|365|335|304|274| |273|242|214|183|153|122|92| 61| 30|365|334|304| |304|273|245|214|184|153|123| 92|61| 31:365|335| |334303|275|244 214|183|153|122| 91| 61 30|365 Suppose the number of days between the 10th of April and 10th of October were required; under the column of

Nov.
Dec.

April at the top of the table, look for October, and you find 183, the number required.

If the days in the given months be different, their difference must be added or subtracted, to or from the tabular number. Thus, from the 10th of April to the 20th of Oc tober, is 183+10=193 days. And from the 20th of April to the 10th of October, 183-10=173 days.

If the time exceed a year, 365 days must be added for each year.

Case 5.

When the amount, rate, and time are given to find the principal.

RULE.

As the amount of 100 dollars, at the rate and time given, is to 100 dollars, so is the amount given to the principal required.

EXAMPLE.

1. What principal being put to interest for 9 years, at 5 per cent. per annum, will amount to 725 dollars?

9

5

45 100

As 145 : 100 :: 725 : 500 Ans.

2. What principal being put to interest for 12 years, at 6 per cent. per annum, will amount to 2752 dollars?

Ans. 1600 dolls. 3. Received 728 dollars as payment in full for a note with 5 years interest thereon, at 6 per cent. per annum; for how much was the note given? Ans. 560 dolls. 4. What sum put to interest for 4 years, at 7 per cent. per annum, will amount to 1638 dollars?

Ans. 1260 dolls.

5. Received 2000 dollars as payment in full for a bond, with 5 years interest thereon, at 5 per cent. per annum; what principal did the bond contain?

Ans. 1553 dolls. 39 cts. 88m.