1. At an annual simple interest rate of 5%, how many years will it take for the interest on ₹6000 to become ₹1500?

(a) 3 years (b) 30 years (c) 5 years (d) 15 years

2. If a sum of money becomes 4 times its original amount in *n* years at a fixed annual compound interest rate, then in how many years will it become 4 times?

3. If a certain amount of money doubles in \(n\) years at a fixed annual compound interest rate, then in how many years will it become four times?

4. At an annual interest rate of 5%, for how many years will the interest on 300 rupees amount to 120 rupees?

(a) 4 (b) 8 (c) 12 (d) 12\(\frac{1}{2}\)

5. If a sum of money doubles in \(n\) years at a fixed annual compound interest rate, then in how many years will it become 4 times?

6. 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?

7. A farmer deposited some money in the village post office. After 4 years, he found that the total amount including interest had become ₹434. He calculated that the interest he received was \(\frac{6}{25}\) of his principal amount. Find how much money he had originally deposited and what annual rate of simple interest the post office gave.

8. A borrowed ₹960 from B at an annual simple interest rate of 6%, with the condition that the loan will be repaid over the next 4 yearly installments. In the first 3 installments, A will pay only one-fourth of the principal each year. In the final (4th) installment, A will pay the remaining principal along with the total interest accrued over the 4 years. Find the total amount A will pay at the end of the 4th year.

9. If the annual rate of interest and the time in years are equal, then in how many years will the interest on ₹324 amount to ₹16?

(a) \(2\cfrac{2}{9}\) (b) \(2\cfrac{1}{9}\) (c) \(2\cfrac{4}{9}\) (d) \(2\cfrac{5}{9}\)

10. Jayanta deposits ₹100 on the first day of each month in a monthly savings scheme. He continues this for one year. If the annual simple interest rate is 6%, how much total amount (principal + interest) will he receive at the end of the year?

11. In how many years will the amounts of simple interest and compound interest be equal for the same principal at the same annual interest rate?

(a) 3 years (b) 2 years (c) 1 years (d) \(\frac{1}{2}\)

12. A person borrows ₹2,40,000 at an annual simple interest rate of 12% to build a house. One year after taking the loan, they start renting out the house for ₹5,200 per month. After how many years from taking the loan will the rental income be enough to repay the entire loan along with the accrued interest?

13. At an annual simple interest rate of 4%, in how many years will the interest on ₹1200 be ₹64?

14. Write down the calculation to determine in how many years a sum of money will double at an annual simple interest rate of 6%.

15. Write down the calculation to determine in how many years a simple interest of ₹168 will be earned on a principal of ₹600 at an annual rate of 8%.

16. Rekhadidi deposited ₹10000 from her savings into two separate banks at the same time. One bank offers an annual simple interest rate of 6%, while the other offers 7%. If she received a total of ₹1280 as interest after 2 years, calculate and write how much she deposited in each bank.

17. Rahmat Chacha borrowed ₹240000 from a bank at an annual simple interest rate of 12% to build a house. One year after borrowing, he started renting out the house for ₹5200 per month. Calculate and determine after how many years from borrowing he will be able to repay the bank loan along with interest using the rental income.

18. At an annual simple interest rate of 5%, a person deposits some money in the bank. After 5 years, how much total amount will he receive, if the principal is 12,500 rupees less than the total amount (principal + interest?

19. If a certain amount of money triples in 20 years, then at the same simple interest rate, in how many years will it double?

20. If the total amount becomes 966 rupees at an annual simple interest rate of 3% in 5 years, the principal amount will be -

(a) 480 rupees (b) 408 rupees (c) 404 rupees (d) 840 rupees

21. In how many years will the ratio of the principal and the interest earned become 10:3 at a simple interest rate of 10% per annum?

(a) 12 years (b) 3 years (c) 10 years (d) 13 years

22. If the annual simple interest on a principal is \(\cfrac{1}{9}\) of it, then what will be the accumulated amount in 4 years if the total sum becomes 1326 rupees?

(a) ₹ 1080 (b) ₹ 1120 (c) ₹ 918 (d) ₹ 750

23. At an annual simple interest rate of 8%, how much interest will make the principal amount grow to \(\cfrac{7}{5}\) times its original value?

(a) 4 years (b) 5 years (c) 6 years (d) 7 years

24. 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%

25. 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%

26. ₹1200 is lent at an annual interest rate of 6\(\frac{1}{4}\)% and ₹1000 is lent at an annual interest rate of 4\(\frac{1}{3}\)% on the same day. After how much time will the amounts (principal + interest) of both loans become equal?

(a) 20 years (b) 24 years (c) 15 years (d) 30 years

27. What annual rate of simple interest will make the interest on a sum over 10 years equal to \(\cfrac{2}{5}\) of the total amount?

(a) \(6\frac{1}{3}\%\) (b) \(6\%\) (c) \(6\frac{2}{3}\%\) (d) \(2\frac{1}{6}\%\)

28. If the simple interest on ₹850 for 3 years and on ₹1250 for 4 years at the same rate amounts to ₹302 in total, then what will be the annual rate of interest?

(a) 3% (b) 5% (c) 7% (d) None of the above

29. At an annual simple interest rate of \(\cfrac{r}{2}\%\), the amount after \(t\) years on ₹\(2p\) becomes \(\left(2p + \cfrac{prt}{100}\right)\).

30. A man takes a loan of ₹500 at 6% simple interest per annum. Exactly two years after taking the first loan, he takes a second loan of ₹900 at 4% simple interest per annum. After how many years from the time of the first loan will the interest amounts on both loans be equal? Also, what will be the total interest on both loans at that time?