1. 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 \(\cfrac{a^3}{60}\)?

2. What would be the annual simple interest rate (percentage) if the interest for 4 years on a certain amount is \(\cfrac{8}{25}\) of the principal?

3. At an annual simple interest rate of 6%, the interest for 5 months is \(\cfrac{x}{10}\) rupees. What will the principal be?

(a) ₹ 2x (b) ₹ 4x (c) ₹ 10x (d) ₹ 20x

4. At an annual simple interest rate of 10%, if the interest for 5 years is x rupees, then the principal amount:

(a) ₹ 2x (b) ₹ 4x (c) ₹ 10x (d) ₹ 20x

5. 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

6. If the simple interest for \(n\) years at an annual rate of \(r\%\) is \(\frac{pnr}{25}\) rupees, then the principal amount will be _____ rupees.

7. 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

8. 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?

9. If the simple interest on a certain principal for 2 years at an annual rate of 15% is ₹160, find the compound interest.

(a) ₹ 205 (b) ₹ 172 (c) ₹ 200 (d) none of the above

10. If the total simple interest for 5 years is \(\cfrac{1}{5}\) of the principal, determine the annual simple interest rate.

(a) 4% (b) 5% (c) 10% (d) 25%

11. At an annual simple interest rate of \(x\%\), if the total interest on a principal amount for \(y\) years is \(\cfrac{xyz}{25}\) rupees, then the principal amount is –

(a) ₹ 2z (b) ₹ 4z (c) \(\cfrac{z}{2}\) (d) \(\cfrac{z}{4}\)

12. Fatima Bibi deposited ₹100 on the first day of each month in a monthly savings scheme. She continued this for one full year. If the annual simple interest rate is 6%, let us calculate the total amount (principal + interest) she would receive at the end of the year.

13. If the simple interest on a certain principal for 1 year is ₹50 and the compound interest for 2 years is ₹102, then calculate and write the amount of the principal and the annual rate of interest.

14. 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

15. If the interest on a principal for 5 years is \(\cfrac{1}{4}\) of the principal, then the annual interest rate will be –

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

16. 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

17. At an annual simple interest rate of 12%, if the ratio of principal to interest after \(x\) years is 25:24, what is the value of \(x\)?

(a) 8 (b) 10 (c) 12 (d) 5

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

19. Which one will be less: the simple interest for 2 years or the compound interest with annual compounding for 2 years, on a fixed principal, if the rate of interest is the same?

20. ₹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)?

21. At an annual interest rate of 10%, compounded semi-annually, the difference between the compound interest and simple interest over 2 years is ₹124.05. Find the principal amount.

22. If the simple interest and compound interest on a certain principal for 2 years are ₹8400 and ₹8652 respectively, then determine the principal and the annual rate of interest.

23. If the difference between the compound interest and the simple interest on a certain sum of money for 2 years at an annual interest rate of 9% is ₹129.60, then find the principal amount.

24. Sure! The Bengali sentence: **"কোনো মূলধন বার্ষিক 6 \(\frac{1}{4}\)% সরল সুদের হারে কত বছরে দ্বিগুণ হবে তা লিখি ।"** translates to English as: **"Write how many years it will take for a principal to double at an annual simple interest rate of 6 \(\frac{1}{4}\)%."** Would you like help solving this too?

25. 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?

26. If the interest on a certain amount of money at an annual rate of 5% for 8 years is ₹246 more than the interest at an annual rate of 7% for 4 years, what is the principal amount?

(a) ₹ 5020 (b) ₹ 2000 (c) ₹ 2050 (d) ₹ 2005

27. The difference in interest for ₹550 over 4 years at annual rates of 6% and 8% is—

(a) ₹ 22 (b) ₹ 88 (c) ₹ 44 (d) ₹ 11

28. 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%

29. If the simple interest on a certain amount at an annual interest rate of 8% for 2 years is ₹850, then what will be the compound interest for the same period?

(a) ₹ 1684 (b) ₹984 (c) ₹ 884 (d) none of the above

30. What is the difference between the compound interest and simple interest on ₹1950 at an annual interest rate of 8% for 2 years?

(a) ₹ 18 (b) ₹ 12.48 (c) ₹ 48.12 (d) ₹ 24