1. What sum must I invest to yield $54 interest per year at 6%? To yield $90 in two years at 5%?

2. At what per cent. must I invest $600 to produce $72 interest in three years? To obtain $42 on $420 in two years? 3. For how long a time must I put $350 at 8% interest to produce 84?

4. What sum must be put to interest at 3% that principal and interest may amount to $590 in 6 years? At 4%, that the amount shall be $1287 in 1 yr. 6 mo. ? '

1. What sum of money must be invested at 4% to support 10 orphans in an asylum at a cost of $180 a year each ?

2. How much must be paid for a house, that it may yield $840 per year rent at 8% on the cost ?

3. Mr. Jones buys a house for $9250 and rents it for $740 a What per cent. does he receive on his investment ?

year.

4. For how long a time must $756 remain at interest to double itself at 6%? At 10%? At 8%?

5. At what rate per cent. must a sum of money be invested to double itself in 16 years 2

6. What sum at 42% interest will yield an annual income of $1800.

7. At what rate must $2300 be invested to yield an annual income of $161 ?

8. For what time must $2580 remain at 8% interest to amount to $3612 ?

9. What sum must a father invest for his daughter, now 4 years old, so that at 20 she may have $1000 ?

10. What sum in 6 years, at 4%, will yield the same interest that $850 will yield in 3 years at 6% ?

Present Worth.

234. The present worth of a debt, payable at a future time without interest, is such a sum of money that, if put at interest, it would amount to the debt when it becomes due.

235. The difference between the face of a debt and its present worth is True Discount.

True discount is so called to distinguish it from bank discount. True discount is the interest on the present worth of a debt. Bank discount is interest on the whole debt. The difference is the interest on the true discount.

Example. Find the present worth and the true discount of a debt of $48.36, payable in 6 months without interest.

Note. The mode of solving problems in present worth is exactly the same as that of finding the principal, the amount (or debt), time, and rate % being given.

Exact Interest,

In all the foregoing calculations, 30 days have been taken for one month, and 360 days for one year. The interest thus found is greater than if reckoned for exact time, counting 365 days to the year,

236. To obtain Accurate or Exact Interest for any number of days, we find the exact time in days, and take as many 365ths of a year's interest as there are days in the given time.

Example.-1. $350 is at interest from January 16 to March 29, 1880. What is the accurate interest?

Find the interest as in previous cases, also the exact interest :

Common Business Method.

237. Bankers, and most other business men, in computing interest for short periods of time, usually take the exact number of days as above, but reckon each day as 1/360 of a year.

This method differs from the preceding in reckoning 360 days to the year instead of 365.

In almost all the States 3 days, called “days of grace,” are allowed for the payment of a note after the promised time of payment.

Example.-1. Find the interest of $150 from April 27 to June 26, 1885, at 9%.

238. A Promissory Note is a written promise to pay a stated sum of money, either on demand or in a certain time, to some person named in the note.

239. Banks loan money on notes. For doing so, they charge interest on the note. This they deduct from the amount of the note at the time of making the loan. The remainder is called the avails or proceeds of the note.

240. A note is said to be payable at the time promised. It matures three days later (i. e., on the last day of grace). It is then legally due.

241. The two dates showing when a note is payable, and when legally due, are written thus: Aug. 5/8, which is read August fifth, eighth.

242. Bankers usually reckon interest according to the Common Business Method. (See Art. 237.)

Example. Find the bank discount and proceeds of a note for $645, payable Sept. 20, discounted at 6% July 16.

Find the interest and proceeds of a note for

2. $450, dated Aug. 10, due Nov. 8, 1885, discounted at 6%.