9. What is the interest of $10 for 4 years and 2 months, at 7 per cent.?

10. What is the amount of $150 for 4 years and 1 month, at 7 per cent.?

11. Required the amount of $200 for 2 years and 2 months, at 4 per cent.

12. Required the amount of $145 for 6 years and 3 months, at 8 per cent.

13. Required the amount of $400, at 3 per cent., for 2 years, 2 months and 20 days.

14. What is the amount of $140 for 5 years, 4 months and 10 days, at 7 per cent.?

15. What is the amount of $200 for 2 years, 6 months and 14 days, at 6 per cent.?

16. What is the interest of $15 for 6 years, 4 months and 2 days, at 8 per cent.?

17. What is the amount of $360 for 8

months and 12 days, at 6 per cent.?

years,

18. What is the amount of $180 for 6 years,

months and 13 days, at 7 per cent.?

7

19. What is the amount of $200 for 5 years and 9 months, at 4 per cent.?

20. What is the amount of $140 for 3 years, months and 18 days, at 8 per cent.?

8

21. What is the amount of $175 for 4 years, 4 months and 9 days, at 61 per cent.?

22. What is the amount of $140 for 3 years, 6 months and 18 days, at 3 per cent.?

23. Required the amount of $160 for 9 years, at 5 per cent.

24. Required the amount of $300 for 5 years, 8 months and 6 days, at 6 per cent.

25. What is the amount of $250 for 3 years, 6 months and 24 days, at 7 per cent.?

26. What is the amount of $500 for 1 year, 5 months and 20 days, at 10 per cent.?

LESSON XLVI.

1. If the interest of $120 for 1 year is $9, what is the interest of $60? Of $20? Of $10 ?

2. If the interest of $400 for 1 year is $24, what is the interest of $100? Of $10? Of $1? 3. If the interest of $12 for 5 years is $3.60, what is the interest of $6? Of $60? Of $300? 4. If the interest of $160 for 2 years is $18, what is the interest of $80? Of $40? 5. If the interest of $280 what is the interest of $70? 6. If the interest of $100 what will it be for 6 years? 4 years? For 1 year?

for 3 years is $46, Of $140?

for 3 years is $20, For 10 years? For

7. If the interest of $180 for 2 years is $23, what is it for 3 years? For 7 years? For 1 year?

8. If the interest of $200 for 3 years is $27, what is its interest for 1 year? For 1 month? For 4 months? For 7 months?

9. If the interest of $200 for 1 month is $1, what is it for 15 days? For 5 days? For 1 day?

10. If the interest of $140 for 1 year and 4 months is $10, what is it for 8 months? For 4 months? For 2 months? For 1 month?

11. The interest of $240, at 6 per cent., is $27; what is it at 3 per cent.? At 1 per cent.?

12. The interest of $320, at 7 per cent., is $15; what is it at 1 per cent.? At 8 per cent. ?

13. If the interest of $100 for 3 years is $21, what is the rate per cent.?

14. If the interest of $300 for 1 year is $21, what is the rate per cent.?

15. What is the interest of $100 for 4 years, at 1 per cent.? If the interest of $100 for 4 years is $20, what is the rate per cent. ?

16. If the interest of $300 for 2 years is $48, what is the rate per cent.?

NOTE. Since the interest of $300 for 2 years, at 1 per cent., is $6, $48 will be as many per cent. as $48 contains times $6.

17. If the interest of $200 for 2 years is $12, what is the rate per cent.?

18. If the interest of $400 for 3 years is $24, what is the rate per cent.?

19. If the interest of $150 for 3 years and 4 months is $35, what is the rate per cent.?

20. If the interest of $25 for 1 year and 8 months is $1, what is the rate per cent.?

NOTE. The interest of $25 for 1 year and 8 months, at 1 per cent., is 13 times Too of $25=ʊ of $25= $12, and the rate per cent. required will be as many per cent. as $11⁄2 is contained times in $1, which are 12-23 times. Therefore, 23 per cent. is the answer.

21. If the interest of $50 for 1 year and 3 months is $3, what is the rate per cent.?

22. If the interest of $75 for 4 years and 2 months is $12, what is the rate per cent.?

23. A man paid $8 for the use of $48 for 1 year and 4 months; what was the rate per cent.?

24. John Niles lends Harry Hubbard $30 for 2 years and 6 months; Harry has to pay at the end of the time $36; what is the rate per cent.?

NOTE.The principal, $30, has to be paid back, and is of course a part of the $36; the remainder, $6, is the interest, by which the rate per cent. is to be found.

25. A note of $100, being on interest 2 years and 2 months, amounted to $125; what was the rate per cent. ?

26. A gentleman lent $60 for 1 year and 6 months, and received $90; what was the rate per cent.?

LESSON XLVII.

1. What principal, at 10 per cent., is sufficient to gain $6 in 4 years?

NOTE. Since the interest of $1 for 4 years, at 10 per cent., is 40 cents, $6 is the interest of as many dollars as 40 cents or 4 dimes is contained times in $6 or 60 dimes, which are 15; therefore, $15 is the answer.

2. What principal, at 4 per cent., is sufficient in 2 years to gain $8?

3. What is the principal that, in 4 years, at 3 per cent., will gain $6?

4. What principal, at 6 per cent., is sufficient in 5 years to gain $10?

5. What principal is sufficient in 2 years and 4 months, at 4 per cent., to gain $64?

6. What principal is sufficient in 2 years, at 8 per cent., to gain $10?

7. What principal is sufficient in 6 years, at 1 per cent., to gain $20?

8. What principal, at 4 per cent., in 1 year and 7 months, will gain $5?

9. What principal, in 6 years and 4 months, at 6 per cent., will gain $18?

10. What principal is sufficient in 7 years to gain $18, at 7 per cent.?

11. The interest on a note for 4 years and 2 months, at 4 per cent., was $60; what was the principal?

12. If the interest of $50, at 6 per cent., is $6, how long was it on interest?

NOTE. Since $50 at 6 per cent. will require 1 year to gain $3, it will require as many years to gain $6 as $3 is contained times in $6, which are 2 times. Therefore, 2 years is the an

swer.

13. If the interest of $60, at 2 per cent., is $12, how long has it been on interest?

14. How long must $100 be on interest, at 4 per cent., to gain $40?

15. A note of $80, being on interest at 8 per cent., amounted to $160; how long was it on interest?

16. How long must $10 be on interest, at 5 per cent., to gain $3?

17. If the interest of $20, at 4 per cent., is $4, how long a time has it been on interest?

18. If the interest of $50, at 8 per cent., is $12, how long has it been on interest?

19. Required the time that $40 must be on interest, at 2 per cent., to gain $8.

20. A gentleman lent $60, at 6 per cent., and received $140; how long was it on interest?

21. A sum of money is on interest at 6 per cent., how long will it take it to double itself?

NOTE. That is, if it gain 6 per cent. a year, how long will it take to gain 100 per cent.?

22. How long will it take a sum of money to double itself, at 9 per cent.? At 18 per cent. ? 23. A given principal gains of of itself a year; how long will it take it to double itself?

NOTE.of

=

z; if the principal gains of itself in one year, it will take it as many years to gain as much as itself as is contained times in 28, which gives 289 years.

28

24. A given principal gains of of itself a year; how long will it take to double itself? To gain of itself? of itself?

25. If I loan $1200, at 8 per cent. a year, how long will it be in gaining $80?

26. If I loan $500, at 7 per cent. a year, how long will it be in gaining $350 ?