10. What is the interest of $1, for 7 months and 11 days, at 6 per cent.?

11. What is the interest of $1, for 3 years and 9 months, at 6 per cent.?

CASE II.

To find the interest of any given principal, for any given time, at 6 per cent., we have this

RULE.

Find the interest on $1, for the given time, by case I., multiply the interest thus found by the given principal.

Examples.

1. What is the interest of $49.37, for 13 months and 15 days, at 6 per cent.?

In this example we find the interest on $1, for 13 months and 15 days, at 6 per cent., to be $0.0675, which, multiplied by the principal, gives $3.332475, for the interest on $49.37, for the given time.

2. What is the interest of $608.62, for 1 year and 9 months, at 6 per cent.? Ans. $63.9051. 3. What is the interest of $341.13, for 7 years and 9 days, at 6 per cent.? Ans. $143.786295. 4. What is the interest of $100, for 16 years and 8 months, at 6 per cent.?

Ans. $100.

5. What is the interest of $591.03, for 4 years 3 months and 7 days, at 6 per cent.? Ans. $151.402185. 6. What is the interest of $0.134, for 4 months and 3 days, at 6 per cent. ? Ans. 0.002747.

7. What is the interest of $7.50, for 7 months, at 6 per cent.?

8. What is the interest of $371.01, for 4 years and 15 days, at 6 per cent.?

9. What is the interest of $57.92, for 3 years 7 months and 9 days, at 6 per cent.?

10. What is the interest of $329, for 5 years and 13 days, at 6 per cent.?

11. What is the interest of $47.39, for 1 year and 7 months, at 6 per cent.?

CASE III.

To find the interest on any given principal, for any given time, at any given rate per cent., we have this

RULE.

Find the interest on the given principal, for the given time, at 6 per cent., by case II. Then increase, or decrease, this interest by the same part of itself, as it would be necessary to increase, or decrease, 6, in order to make it agree with the given per cent.

Examples.

1. What is the interest of $19.41, for 1 year 7 months and 13 days, at 7 per cent.?

In this example, we find by case II., that the interest of $19.41, for 1 year 7 months and 13 days, at 6 per cent., is $1.886005. Since 6, increased by its sixth part, equals 7, it will be necessary to increase the interest just found, for 6 per cent., by its sixth part, which becomes $2.2003391, for the interest at 7 per cent.

2. What is the interest of $530, for 3 years and 6 months, at 5 per cent.? Ans. $92.75.

In this example it was necessary to decrease the interest at 6 per cent., by its sixth part.

3. What is the interest of $5.37, for 4 years and 12 days, at 8 per cent. ? Ans. $1.73272.

In this example we increased the interest at 6 per cent. by its third part.

4. What is the interest of $4070, for 3 months, at 9 per cent.? Ans. $91.575. 5. What is the interest of $3671, for 6 months, at 10 per cent. ? Ans. $183.55. 6. What is the interest of $4920.05, for 3 months, at 4 per cent. ? Ans. $49.2005.

7. What is the interest of $40.17, for 3 months and 18 days, at 3 per cent. ? Ans. $0.36153.

8. What is the interest of $37.13, for 5 months and 12 days, at 41 per cent. ? Ans. $0.7518825.

9. What is the interest of $489, for 3 years and 4 months, at 5 per cent. ?

10. What is the interest of $700, for 1 year and 9 months, at 7 per cent.?

NOTE. When the principal is given in English money, we must reduce the shillings, pence, and farthings, to the decimal of a pound; and then proceed as in Federal money.

11. What is the interest of £75 13s. 6d., for 3 years and 5 months, at 6 per cent.?

In this example, 13s. 6d., reduced to the decimal of a pound, is 0.675, so that our principal is £75.675; the interest on £1, for 3 years and 5 months, at 6 per cent., is £0.205, which, multiplied into £75.675, gives £15.513375=£15 10s. 3d., for the interest required.

12. What is the interest of £14 5s. 31d., for 4 years 6 months and 14 days, at 7 per cent.? Ans. £4 10s. 7-12 d.

13. What is the interest of £1 7s. 6d., for 2 years and 6 months, at 4 per cent.? Ans. £0 3s. 1d.

14. What is the interest of £105 10s. 6d., for 9 months,

PARTIAL PAYMENTS.

66. When notes, bonds, or obligations, receive partial payments, or endorsements, we must use the following rule, which was given by Chancellor KENT, in the New York Chancery Reports:

RULE.

"The rule for casting interest, when partial payments have been made, is to apply the payment, in the first place, to the discharge of the interest then due. If the payment exceed the interest, the surplus goes towards discharging the principal, and the subsequent interest is to be computed on the balance of principal remaining due. If the payment be less than the in. terest, the surplus of interest must not be taken to augment the principal; but interest continues on the former principal until the period when the payments, taken together, exceed the interest due, and then the surplus is to be applied towards discharging the principal; and interest is to be computed on the balance, as aforesaid."

Examples.

UTICA, Nov. 1, 1837. 1. For value received, I promise to pay Thomas Jones, or order, the sum of six hundred and twenty dollars, on demand, CHARLES BANK.

with interest.

The following endorsements were made on this note :

1838, Oct. 6, there was endorsed

$61.07

89.03

107.77

200.50

What was the balance due, Oct. 15, 1840, allowing 7 per

cent. interest?

The amount of note, or principal, is

$620.000

Interest on the same, up to Oct. 6, 1838, is

40.386

Amount due on note, Oct. 6, 1838, is

660.386

The first endorsement is

61.070

599.316

Interest from Oct. 6, 1838, to March 4, 1839, is

17.247

Amount due March 4, 1839, is

616.563

The second endorsement is

89.030

527.533

Interest from March 4, 1839, to Dec. 11, 1839, is 28.413

The third endorsement is

555.946

107.770

448.176

Interest from Dec. 11, 1839, to July 20, 1840, is 19.085

467.261

The fourth endorsement is

200.500

266.761

Interest from July 20, 1840, to Oct. 15, 1840, is

4.410

Ans. 271.171