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

2. 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)?

3. 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%

4. At an annual simple interest rate of \(x\%\), if the interest on a principal amount for \(x\) years is \(x\) rupees, what is the principal amount?

(a) \(x\) rupees (b) \(100x\) rupees (c) \(\cfrac{100}{x}\) rupees (d) \(\cfrac{100}{x^2}\) rupees

5. If the ratio of principal to interest-principal in a year is 8:9, then what is the annual simple interest rate?

(a) 12\(\cfrac{1}{2}\)% (b) 15\(\cfrac{1}{2}\)% (c) 12% (d) 15%

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

7. If the ratio of a principal amount and its amount after 5 years is 5 : 6, then find the annual simple interest rate.

8. 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.

9. If the ratio of principal to amount after 1 year is 4:9, then the annual simple interest rate will be 5%.

10. If the ratio of the principal to the amount after annual compound interest is 25 : 27, then what is the rate of interest?

(a) 6% (b) 8% (c) 10% (d) 12%

11. If the ratio of principal to amount after 1 year is 4:9, then the annual simple interest rate is 12.5%.

12. At an annual simple interest rate of \(\cfrac{a}{5}\)%, if the interest on ₹\(a^2\) for \(\cfrac{a}{3}\) years equals the principal amount, then what is the value of \(\cfrac{a^3}{60}\)?

13. If the ratio of a certain principal amount to its compound amount after a certain period is 15:21 and the annual simple interest rate is 5%, then the duration of time is –

(a) 4 years (b) 2 years (c) 8 years (d) 10 years

14. If the ratio of principal to amount after one year is \(8:9\), then the annual simple interest rate is _____%.

15. Here’s the English translation of your question: At a certain fixed rate of simple interest, if a principal amount becomes double in \(x\) years and triple in \(y\) years, then what is the ratio \(x:y\)?

(a) 2:3 (b) 1:2 (c) 3:2 (d) 2:1

16. 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?

17. If the total simple interest for \(n\) years at an annual rate of \(x\%\) is \(\frac{pnr}{25}\), > then what is the principal amount?

(a) 2p rupees (b) 4p rupees (c) \(\cfrac{p}{2}\) rupees (d) \(\cfrac{p}{4}\) rupees

18. At an annual simple interest rate of \(x\%\), if the interest on a principal in \(x\) years is \(x\) rupees, then the amount of the principal is –

(a) \(x\) rupees (b) \(100x\) rupees (c) \(\cfrac{100}{x}\) rupees (d) \(\cfrac{100}{x^2}\) rupees

19. At an annual simple interest rate of \(r\%\), if the total interest on a principal for \(n\) years is \(\cfrac{pnr}{25}\) rupees, then the amount of the principal is –

(a) \(2p\) rupees (b) \(4p\) rupees (c) \(\cfrac{p}{2}\) rupees (d) \(\cfrac{p}{4}\) rupees

20. 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

21. If the ratio of the principal and the total amount is 10:11, what is the annual interest rate?

(a) 10% (b) 11% (c) \(10\cfrac{1}{11}\)% (d) 12%

22. If the ratio of the principal to its total amount after one year is 25:28, then the annual interest rate is—?

(a) 3% (b) 12% (c) 10\(\frac{5}{7}\)% (d) 8%

23. 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?

24. ₹1200 is deposited for 4 years and ₹2000 for 3 years in a bank at the same rate of simple interest. If the total interest earned is ₹594, what is the annual rate of interest (percentage)?

25. If the total simple interest on a principal amount at an annual rate of \(x\%\) for \(y\) years is \(\frac{pyx}{25}\) rupees, then the principal amount will be:

(a) \(2p\) rupees (b) \(4p\) rupees (c) \(\cfrac{p}{2}\) rupees (d) \(\cfrac{p}{4}\) rupees

26. If the difference between the compound interest and simple interest on a certain principal for 2 years at an annual rate of 5% is ₹25, then what is the amount of the principal?

27. If a certain principal amounts to ₹1500 at an annual interest rate of 10% and ₹1300 at an annual interest rate of 6% after a fixed period, what is the principal?

(a) ₹ 500 (b) ₹ 1000 (c) ₹ 1800 (d) ₹ 1600

28. If ₹1413 triples in 25 years at an annual simple interest rate of \(r\%\), what is the value of \(r\)?

(a) 8 (b) 15 (c) 20 (d) 5

29. If the ratio of a certain principal amount to the interest accrued over a given period is 20:7, and the annual simple interest rate is 6%, then the duration of time is –

(a) 6 years (b) 5\(\cfrac{5}{6}\) years (c) 6\(\cfrac{5}{7}\) years (d) none of the above

30. If the ratio of principal to interest for 5 years is 16:9, find the annual interest rate.

(a) 11.25% (b) 13% (c) 12.25% (d) 16%