1. At what annual percentage rate will a certain amount of money double in 16 years?

(a) 5% (b) 8\(\frac{1}{2}\)% (c) 6\(\frac{1}{4}\)% (d) 8\(\frac{1}{4}\)%

2. At what annual interest rate will the interest on a principal amount become \(\cfrac{5}{16}\) of the principal in 6\(\cfrac{1}{4}\) years?

(a) 3% (b) 4% (c) 5% (d) 6%

3. At an annual interest rate of 4%, what principal amount will yield at least ₹80 difference between simple interest and compound interest over 2 years?

4. At an annual compound interest rate of 5%, what principal amount will yield ₹315.25 as compound interest in 3 years?

5. If \(\frac{1}{6}\) of a principal amount is earned as annual simple interest, what will be the percentage rate of interest?

(a) 10\(\cfrac{2}{3}\%\) (b) 16\(\cfrac{2}{3}\%\) (c) 12% (d) 9\(\cfrac{2}{3}\%\)

6. At an annual compound interest rate of 5%, what principal amount will yield a compound interest of 615 currency units in 2 years?

7. Aman borrowed ₹25,000 for 3 years, with annual compound interest rates of 4% for the first year, 5% for the second year, and 6% for the third year. What amount will Aman repay (including principal and interest) at the end of 3 years?

8. At an annual simple interest rate of 5%, what amount of principal will yield a monthly interest of 1 rupee?

(a) ₹ 120 (b) ₹ 200 (c) ₹ 240 (d) ₹ 20

9. If a principal amount doubles in 10 years, what will be the annual simple interest rate ?

(a) 5% (b) 10% (c) 15% (d) 20%

10. What principal amount will generate ₹1 as simple interest for 1 day at an annual rate of 10%?

(a) ₹7300 (b) ₹1825 (c) ₹3650 (d) ₹10950

11. If the time period and the annual simple interest rate are equal, then at what annual interest rate will the interest amount be \(\cfrac{1}{25}\) of the principal?

(a) 25% (b) 10% (c) 2% (d) 2.5%

12. At what annual percentage rate of interest will 325 rupees yield an interest of 52 rupees in 4 years?

(a) 3% (b) 4% (c) 5% (d) 6%

13. At what annual interest rate will a principal amount become three times its original value in 25 years?

(a) 6% (b) 8% (c) 10% (d) 12.5%

14. At what annual percentage rate of interest will the interest on an amount in 4 years become \(\cfrac{1}{6}\) of the total amount?

(a) 4% (b) 5% (c) 6% (d) 8%

15. What should be the annual interest rate for a principal amount to double in 6 years?

(a) 12% (b) 12\(\cfrac{1}{2}\)% (c) 16% (d) 16\(\cfrac{2}{3}\)%

16. What should be the annual rate of simple interest (in percentage) so that the interest earned in 4 years becomes \( \frac{2}{5} \) of the principal amount?

17. What should be the annual rate of simple interest (in percentage) so that the interest earned in 4 years becomes \(\frac{8}{25}\) of the principal amount?

18. If a principal amount doubles in \(x\) years, what is the annual rate of simple interest?

19. If a principal amount doubles in 8 years at an annual compound interest rate of \(r\%\), then in how many years will it become four times?

20. If interest is compounded every 6 months, then at an annual compound interest rate of 10%, what will be the compound amount and compound interest on ₹8000 for 1½ years?

21. If the ratio of principal to amount after 1 year is 20 : 21, what is the annual rate of simple interest (in percentage)?

22. A farmer deposits ₹100 at the post office on the first day of every month. If the annual rate of simple interest is 5%, what will be the total amount (principal + interest) he receives at the end of the year?

23. If after one year the ratio of the principal to the amount (principal + interest) is 10 : 12, what is the annual rate of simple interest (in percentage)?

24. At an annual interest rate of 4%, what will be the total amount (including interest) on ₹450 after 3 years?

(a) ₹ 135 (b) ₹ 180 (c) ₹ 504 (d) ₹ 6000

25. If a principal amount is invested at an annual simple interest rate of 6%, in how many years will it double?

26. Mr. Amal bequeaths ₹56,000 in his will for his two sons aged 13 and 15 in such a way that, when they each turn 18, the simple interest earned at an annual rate of 10% will be equal to the principal for each. What will be the allocated amount for each son in the will?

27. If the principal is \(p\) rupees and the annual compound interest rates for the first, second, and third years are \(r_1\%\), \(r_2\%\), and \(r_3\%\) respectively, then what will be the total compound amount after 3 years?

28. What principal amount will become ₹930 in 6 years at an annual simple interest rate of 4%?

(a) ₹ 890 (b) ₹ 750 (c) ₹ 690 (d) ₹ 520

29. If the ratio of the principal amount to its increased value after one year is 25:27, then what will be the annual interest rate?

(a) 2% (b) 4% (c) 6% (d) 8%

30. At an annual \(5\%\) compound interest rate, what will be the compound principal of \(80,000\) taka after \(2\cfrac{1}{2}\%\) years?