9. What number increased by 27% of itself equals 508? 10. What number increased by 331% of itself equals 492? 11. What number increased by 163% of itself equals 329? 12. What number increased by 62% of itself equals 910? 13. A man owes $15400, which is 10% more than his property is worth. What is the value of his property?

14. A man sold a horse for $345, which was 15% more than it cost him. How much did it cost?

15. A clerk's salary was increased 30%, and now it is $1950. What was it before the increase?

How

16. A man expended $3750 in repairs upon his house. This sum was 25% more than the cost of the house. Imuch did it cost?

17. The number of pupils in a certain school during 1876 was 872, which was 9% more than the number in attendance during 1875. What was the attendance during 1875?

CASE V.

324. To find the Base when the Difference and Rate are given.

1. A gentleman sold 25% or 4 of the number of his horses and had 15 left. How many had he?

2. By selling coal at $6 per ton a coal dealer lost 20% or of the cost. What was the cost?

3. A grocer sold sugar at 9c. per pound, and lost 10% or of the cost. What did it cost?

4. A merchant sold cloth at $.75 per yard, thereby losing 25% of the cost. What was the cost?

5. A man's monthly expenses are 331% less this year than last year. This year they are $120; what were they last year? 6. A certain number diminished by 20% of itself is 36. What is the number?

7. What number diminished by 10% of itself equals 45?

8. After subtracting from a number 37% of it, the remainder is 25. What is the number?

9. What number diminished by 27% of itself equals 401.5?

RULE.-Divide the difference by 1 minus the rate.

10. What number diminished by 36% of itself equals 336? 11. What number diminished by 40% of itself equals 432? 12. What number diminished by 55% of itself equals 285? 13. What number diminished by 28% of itself equals 307? 14. A clerk, after paying out 75% of his salary, had $450 left. What was his salary?

15. A farmer, after selling 30% of his wheat, found that he had 350 bushels left. How much had he at first?

16. A man sold some land for 30% less than he asked for it, getting $29.24 per acre. What was his asking price? 17. A regiment losing 15% of its men, had 527 left. How many had it at first?

18. A speculator lost 10% of his money during the year 1875 and 10% of the remainder during 1876. He then had $40500 left. How much had he at first?

19. A merchant's profit in 1876 was $10318, which was 23% less than in 1875. What was his profit in 1875?

of the amount of for one year, how

325. 1. When a sum equal to 5% money lent is paid for the use of it much will be paid for the use of $100 for 1 year? For 2 years?

2. When the allowance for the use of money is 6% per year, what is the allowance for the use of $100 for 1 year? For 2 years? For 3 years? For 3 years?

3. When the sum paid for the use of money is 8% per year, what must be paid per year for $50? For $500?

4. When the sum paid for the use of money is 12% yearly, what must be paid for the use of $100 for 1 year?

5. When the allowance for the use of money is 8% per year, what must be paid for the use of $100 for 6 months? For 1 month? For month? For month? For month? For 10 days? For 20 days?

6. When 6% is paid per year for the use of money, how much will $500 amount to in 2 years? In 3 years?

7. When $500 is loaned for 14 years at 8% per year, what I will be the amount?

DEFINITIONS.

326. Interest is the sum paid for the use of money.

327. The Principal is the sum for the use of which interest is paid.

328. The Amount is the sum of the principal and interest.

329. The Rate of Interest is the annual rate per

cent.

330. Legal Interest is interest according to rate fixed by law.

331. Usury is interest computed at a higher rate than the law allows.

332. A Note, or Promissory Note, is a written promise to pay a sum of money at a given time.

333. PRINCIPLE.-The interest is equal to the product of the principal, rate, and time expressed as years.

334. When the rate per cent. is not specified in notes, accounts, etc., the legal rate is always understood.

On debts due the United States the rate is 6%.

The following table contains the rates of interest in the United States. The first column gives the legal rate, the second the rate that may be collected if agreed to in writing.

TO COMPUTE INTEREST.

335. 1. What is the interest of $200 for 1 2. What is the interest of $200 for 2 years 3. What is the interest of $300 for 3 years 4. What is the interest of $400 for 11 years

year at 6%?

at 7%?

at 5%?

at 6%?

at 8%? 5. What is the interest of $400 for 3 months at 6%? 6. What is the interest of $600 for 1 month at 6%? 7. What is the interest of $600 for 10 days 8. What is the interest of $500 for 15 days at 8%? 9. What will be the amount of $100 for 2 years at 6%? 10. What will be the amount of $200 for 3 years at 4%? 11. What will be the amount of $300 for 21 years at 6%? 12. What will be the amount of $150 loaned for 11 years at 5%?

13. Find the interest of $234.27 for 2 yr. 7 mo. 12 da. at 6%?

ANALYSIS. Since the interest for 1 year is 6% of the principal, we find .06 of $234.27, which is $14.0562; and since $14.0562 is the interest for 1 year, the interest for 2 years will be twice that sum, which is $28.1124. The interest for 1 month is onetwelfth of the interest for 1 year, or $1.1713; and the interest for 7 mo. and 12 days, or 7 mo., is 73 times $1.1713, or $8.6676. This added to the interest for 2 years, gives the interest for 2 years, 7 months, 12 days. Or,

We may find the interest for 1 year as before, and then for 1 month. We then mul