1. Some money becomes 5 times its original amount in 5 years at simple interest. At the same rate of interest, the time required for that principal to become 17 times is:

(a) 17 years (b) 20 years (c) 18 years (d) 19 years

2. A man left ₹28,000 for his 13-year-old son and 15-year-old daughter with the instruction that, at the age of 18, the amount each receives — including simple interest at an annual rate of 10% — should be equal. Determine the amount allocated to each child.

3. 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?

4. 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?

5. 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

6. At an annual simple interest rate of 10%, determine the time required for a principal amount to double.

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

7. 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.

8. At an annual simple interest rate of x%, the interest and total amount (principal + interest) for ₹12y over 10 months is —

9. 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

10. A principal amount doubles in 20 years at a certain simple interest rate. At the same rate of simple interest, the time required for the principal to become three times will be:

(a) 30 Years (b) 35 Years (c) 40 Years (d) 45 Years

11. 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

12. 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%

13. If a principal amount doubles in 10 years, then the annual simple interest rate is—?

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

14. 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?

15. If the annual simple interest rate is \(6\frac{1}{4}\%\), in how many years will any principal amount double with interest?

(a) 5 years (b) 10 years (c) 16 years (d) 12 years

16. If the ratio of a principal amount to its annual amount with interest is 20:25, then the annual interest rate will be 4%.

17. 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

18. If the principal and the annual simple interest rate remain the same, the total interest is inversely proportional to time.

19. 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?

20. 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?

21. At a fixed time, a certain amount of money amounts to ₹400 at an annual interest rate of 10% and ₹200 at an annual interest rate of 4%. What is the principal?

(a) ₹ \(\cfrac{100}{6}\) (b) ₹ \(\cfrac{100}{3}\) (c) ₹ \(\cfrac{200}{3}\) (d) ₹ \(\cfrac{200}{6}\)

22. If a certain principal becomes 7 times in a fixed period at an annual interest rate of 6%, what should the annual interest rate be for it to become 10 times?

(a) 10% (b) 12% (c) 16% (d) 9%

23. If a certain principal amount accrues to ₹950 at an annual interest rate of 10% and ₹700 at an annual interest rate of 6% over the same period, then the duration of time is –

(a) 13\(\cfrac{3}{19}\) years (b) 3\(\cfrac{3}{19}\) years (c) 19\(\cfrac{3}{13}\) years (d) none of the above

24. 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

25. 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%

26. 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%

27. If the principal and the annual simple interest rate remain unchanged, there is a direct relationship between time and total interest.

28. At an annual interest rate of \(6\cfrac{2}{3}\%\), determine the time required for the amount to become \(1.5\) times the principal.

29. If the ratio of the principal amount to its annual amount with simple interest is 25:28, determine the annual simple interest rate.

(a) 3% (b) 12% (c) 16% (d) 8%

30. 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) \(\cfrac{z}{4}\)