In England the time is always computed in this way, as it is in this country when notes are payable at the end of a certain number of days.

4. What is the time from June 23, 1859, to June 3, 1852 ? Answer. 1 yr. 11 mo. 1 da.

5. What is the time from May 13, 1847 to Oct. 8, 1851 ? 6. What is the time from Jan. 31, 1851. to March 23, 1852 ?

7. What is the time from Nov. 17, 1849, to Dec. 12, 1851? 8. What is the time from Dec. 31, 1848, to July 6, 1850? What is the interest

9. Of $787.36 from May 3, 1843, to Dec. 17, 1845? 10. Of $54.76 from Feb. 14, 1840, to June 2, 1844? 11. Of $476.35 from June 30, 1847, to Dec. 28, 1850? 12: Of $638.29 from May 31, 1851, to Oct. 7, 1852 ? 13. Of $4937.56 from Dec. 19, 1843, to Feb. 16, 1847? 14. Of $481.74 from Jan. 29, 1847, to March 25, 1851? 15. Of $587.60 from Jan. 31, 1850, to July 18, 1852? What is the amount

16. Of $947.84 from May 15, 1850, to June 13, 1851 ? 17. Of $748.67 from Dec. 14, 1849, to May 4, 1851? 18. Of $1546.61 from April 9, 1847, to June 1, 1851 ? 19. Of $917.68 from June 5, 1842, to Jan. 1, 1850? 20. Of $8396.58 from April 30, 1847, to March 22, 1850? 21. Of $1449.13 from Dec. 31, 1850, to March 5, 1852? 22. Jan. 15, 1852, George W. Pratt borrowed $237.50 of A. N. Johnson, and Feb. 13, 1852, he borrowed $438.75 more, agreeing to pay interest at 6 per cent per year. He paid the debts March 8, 1852. What was their amount?

23. I have three notes against Arthur Sumner, viz., one for $548.17, dated Jan. 1, 1851, another for $679.18, dated Jan. 27, 1852, and another for $376.89, dated May 31, 1852. What amount will be due on all of them July 8, 1852?

24. Jan. 1, 1851, I borrowed $3468, with which I purchased flour at $6 per barrel. I sold the flour March 17, 1851, for $6.50 per barrel, cash.

Interest being reckoned at

6 per cent, did I gain or lose by the transaction, and how much?

176. Interest by Days.

(a.) Many business men always reduce the time to days, and compute the interest by the method illustrated below. As a general thing, however, this method is not so convenient as the preceding.

(b.) Since, at 6 per cent per year, the interest for 1 day is of Tobo of the principal, it follows that the interest for any number of days must be as many thousandths of the principal as there are days.

(c.) We may, therefore, find the interest for any number of days, by multiplying the principal by of the number of days, and removing the point three places farther to the left.

It will make no difference with the result, whether we multiply by of the number of days, or by the number of days and divide by 6; but it will usually be better to divide before multiplying.

1. What is the interest of $437.62 for 4 mo. 3 da. ?

be of .123 of the principal, which is .020 of the principal. Tha work carried to mills would be written thus:

$437.62

.020

8.752

218

$8.970 Ans.

2. What is the interest of $54.57 for 4 mo. 20 da.? 3. What is the interest of $397.42 for 8 mo. 15 da. ? 4. What is the interest of $231.48 for 7 mo. 12 da. ? 5. What is the interest of $438.64 for 5 mo. 24 da. ? 6. What is the interest of $281.87 for 5 mo. 9 da.? 7. What is the interest of $581.21 for 6 mo. 24 da.? 8. What is the interest of $83.25 for 2 mo. 21 da. ? 9. What is the interest of $98.37 for 6 mo 18 da.?

177. Interest by Dollars, for Months and convenient Parts of a Month.

(a.) We can frequently compute interest with great ease by first finding the interest for 1 day, 1 month, or 1 year, and getting the required interest from this.

(b.) When the interest for any of the above times is any convenient sum, as 1 dollar, 1 dime, 1 cent, 1 mill, dollar, dollar, &c., the proposed course will be particularly advantageous.

(c.) Since, at 6 per cent per year, the interest of any sum for 1 month is of that sum,

1. The interest of $200 is $1 per month.

2. The interest of $20 is $.10, or 1 dime per month. 3. The interest of $2 is $.01 per month.

1. What is the interest of $200 for 7 mo. 15 da.?

Solution.

- The interest of $200 is $1 per month; therefore for 7 mo. 15 da., or 7 mo., it must be 7 dollars, or $7.50.

What is the interest of $200 for

What is the interest for each of the above-mentioned

14. What is the interest of $100 for 7 mo.?

Solution. Since the interest of $200 is 1 dollar per month, the interest of $100 must be a half dollar per month, and 7 half-dollars, or $3.50, for 7 months.

What is the interest of $100 for ·

15.
9 mo.
?

16. 1 yr.?

What is the interest for each of the above-mentioned

178. Interest by Dollars, when the Time is in Days, or Months and Days.

(a.) Since the interest of any sum for 6 days is .001 of that sum, the interest of 1 dollar for 6 days must be .001 of 1 dollar, which is 1 mill. If the interest of 1 dollar for 6 days is 1 mill, its interest for 1 day must be of 1 mill. Therefore, the interest of $1 is of 1 mill per day.

(b.) From this we have the following statements: At 6 per cent,

1. The interest of $6 is 1 mill per day.
2. The interest of $60 is 1 cent per day.
3. The interest of $600 is 1 dime per day.
4. The interest of $6000 is 1 dollar per day.

NOTE. When the interest is required for months and days, we may reduce the months to days, and then apply the above; or we may find the interest for the months, as in the last article, and then find it for the days, as above. The pupil should remember that the interest of $6 is 3 cents per month, of $60 is 3 dimes per month, and of $600 is 3 dollars per month.

What is the interest for each of the above-mentioned

times

10. Of $60 ? 1 11. Of $600? | 12. Of $6000 ? 13. What is the interest per day of $750?

Solution.

The interest of $6000 being 1 dollar per day, the interest of $750, which is of $6000, must be of 1 dollar per day.

26. What is the interest per month of each of the above

36. What is the interest of $1200 for each of the above

179. When to disregard Cents.

If the time is not very long, the interest of any sum less than a dollar can be computed with sufficient accuracy by referring the principal to the nearest convenient aliquot part of a dollar.

Thus, the interest of 24 cents, for any ordinary time of calculating interest, will differ but a trifle from that of 25 cents, or of a dollar, for the same time; the interest of 35 cents will differ but a trifle from that of 33 cents, or of a dollar, &c.

1. What is the interest of $599.77 for 9 mo. 17 da. ? Solution.-$599.77 = $600 23 cents. The interest of $600 for 9 mo. 17 da. (being $3 per month, and 1 dime per day) is $28.70. As 23

cents is very near 25 cents, its interest must be very near per month, which will be about 1 cent for 9 mo. 17 da. from $28.70 leaves $28.69 as the interest required.

of a cent

This taken