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1. What is the amount of $628.37 for 1 yr. 5 mo. 5 da. at 71 per cent? SOLUTION.- a = $628.37 = Prin.
I of a = b = 52.364 = Int. 16 mo. 20 da. at 6 per cent. of .01 of a = c = 1.571 = " 15 da. at 6 per cent.
btes d = $53.935 = " 17 mo. 5 da. at 6 per cent.
of d = e = 13.484 = “ 17 mo. 5 da. at 1} per cent.
a + d + e= $695.789 = Amt. 17 mo. 5 da. at 77 per cent. (b.) What is the interest of
2. $847.98 for 1 yr. 10 mo. 15 da. at 5 per cent? .3. $3865 for 2 yr. 9 mo. 10 da. at 7 per cent?
4. $594.32 for 9 mo. 19 da, at 41 per cent? 5. $219.74 for 3 mo. 4 da. at 3 per cent? 6. $392.58 from June 9, 1846, to June 3, 1847, at 8 per cent? 7. $936.20 from Oct. 1, 1855, to Nov. 17, 1855, at 1} per cent? (c.) What is the amount of — 8. $540 for 8 mo. 19 da. at 7 per cent?
9. $3600 for 15 mo. 25 da. at 9 per cent? 10. $8293 for 29 mo. 29 da. at 54 per cent? 11. $95.63 from Jan. 1, 1855, to Oct. 31, 1856, at 84 per cent?
12. $289.46 from March 27, 1852, to June 4, 1857, at 52 per cent?
(d.) Although the preceding method may always be employed, it will often, if not usually, be better to
Compute the interest at the given rate for any time for which it may be easily computed, and then take such multiples and parts of this as will give the interest for the required time.
13. What is the amount of $976.25 for 1 yr. 3 mo. 18 da. at 7 per cent ? SOLUTION.
a = $976.25 = Prin.
I of b = c = 17.084 = “ 3 mo.
į of c= d = 3.416 = " 18 da. a+b+c+ d = $1056.087 = Amt. 1 yr. 8 mo. 31 da,
(e.) What is the interest of -
28. Jan. 1, 1857, I bought 1000 bbl. of flour at $8.75 per bbl., borrowing the money at 6 per cent to pay for it. Feb. 1, I sold 1 the flour at $9.25 per bbl., and immediately put the money on interest at 7 per cent. Feb. 15, I sold the remainder at $9.62 per bbl., and put the money received for it on interest at 74 per cent. July 1, I collected the money due me and paid the amount of that which I had borrowed. What was my gain ?
113. Compound Interest. (a.) When interest is to be paid at regular intervals, or, if unpaid, is to be added to the principal to form a new principal on which interest is to be computed, it is called COMPOUND INTEREST.
Note. — The difference between Simple and Compound Interest is that, by the latter, interest is reckoned on interest, while by the former it is not.
(b.) To compute compound interest, we find the amount of the principal at simple interest to the time when the first interest is due; then the amount of this amount to the time when the second interest is due; and so on to the time of settlement. The last amount found is the required amount, and the difference between it and the given principal is the compound interest.
1. To what sum will $432 amount in 1 yr. 8 mo. 15 da. at 4 per cent, payable semi-annually, and what is its compound interest for that time?
2. To what sum will $950 amount in 2 yr. 6 mo. at 6 per cent, payable semi-annually?
3. What is the compound interest of $175.50 for 4 yr. 8 mo. 12 da. at 4 per cent, payable annually ?
4. What is the compound interest of $450 for 3 yr. 9 mo at 9 per cent, payable quarterly ?
5. To what sum will $875.50 amount in 5 yr. 8 mo. 10 da. at 3 per cent, payable annually!
6. To what sum will $1500 amount in 2 yr. 2 mo, at 10 per cent, payable semi-annually?
(c.) The following table shows what part of any principal is equal to its amount at 3, 4, 5, 6, 7, and 8 per cent annual compound interest, for any number of years not exceeding 25.
(d.) The amount of any sum of money, est annual compound interest, for any time and rate mentioned in the table, may be found by multiplying the principal by the appropriate number selected from the table.
7. What is the amount of $562.48 for 8 yr. 4 mo. at 7 per cent?
SOLUTION. — By the table, it appears that the amount of a sum of money for 8 years, at 7 per cent compound interest, is 1.718186 times the principal. Multiplying $562.48 by 1.718186, we have $966.44526128, or, omitting the denominations below mills,
a = $966.445 = Amount for 8 .years. 2} per cent. of a = b = 22.55 = Interest for 4 mo.
a + b = c = $988.995 = Amount for 8 yr. 4 mo..
What is the amount at compound annual interest of —
PRACTICAL APPLICATIONS OF INTE
REST AND PERCENTAGE.
114. Promissory Notes. (a.) A PROMISSORY Note, a NOTE OF Hand, or, as it is more commonly called, a Note, is a written promise to pay a specified sum of money.
(b.) The person who signs a note is called the PROMISOR, or MAKER of the note, and the one to whom it is made payable is called the PROMISEE. The one who has legal possession of it is called the HOLDER of the note. The FACE OF A NOTE is the sum for which it is given.
ILLUSTRATIONS. - In Form 1, Elbridge Clapp is the Promisor or Maker of the note, and Hiram A. Pratt is the Promisee. Mr. Pratt will be the Holder of the note until it is paid, or till he transfers it to some other person. The FACE OF THE NOTE is $500.
(c.) The words “VALUE RECEIVED" should always be placed in a note, as an acknowledgment that the maker gave it in conside ration of something of equivalent value.