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

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

2. If a principal doubles in 5 years at a certain simple interest rate, then in how many years will it quadruple at the same rate?

(a) 12 (b) 14 (c) 15 (d) 16

3. If a principal amount doubles in 20 years at a certain simple interest rate, then in how many years will it triple at the same simple interest rate?

4. If a principal doubles in 20 years with simple interest, then at the same simple interest rate, the principal will become four times in –

(a) 30 years (b) 40 years (c) 80 years (d) 60 years

5. If a principal amount doubles in 20 years at a certain simple interest rate, then at the same rate, the principal will triple in – ?

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

6. 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

7. 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

8. 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

9. Under the same simple interest rate, a principal amount grows to 7000 rupees in 5 years and 8200 rupees in 8 years. What is the rate of interest?

(a) 4% (b) 6% (c) 8% (d) 10%

10. 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?

11. 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.

12. If a sum of money doubles in \(n\) years at an annual compound interest rate, then it will become four times in –

(a) \(2n\) years (b) \(\cfrac{n}{2}\) years (c) \(3n\) years (d) \(\cfrac{n}{3}\) years

13. 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

14. If the simple interest on 700 rupees for 3 years is 210 rupees, then the annual interest rate will be?

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

16. A principal amount doubles in 20 years at a certain simple interest rate. At the same rate, in how many years will the principal become three times?

17. If the difference between the compound interest and simple interest on a certain sum for 3 years at an annual rate of 10% is 930 rupees, then what is the principal amount?

18. At an annual simple interest rate of x%, if the interest earned in x years is x rupees, then the principal amount is —

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

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

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

20. 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?

21. If the simple interest and compound interest on a certain principal for 2 years are 840 rupees and 869.40 rupees respectively, then let’s calculate and write down the principal amount and the annual rate of interest.

22. Translate: If the simple interest on a certain principal for \(n\) years at a rate of \(r\%\) is \(\frac{pnr}{25}\) rupees, then the amount of the principal is –

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

23. Some money amounts to 944 rupees in 3 years at simple interest. If the annual rate of interest increases by 25%, then the same money amounts to 980 rupees in the same time. Find the rate of interest and the principal.

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

25. A sum of money triple itself in 20 years then, find the rate of simple interest.

(a) 10% (b) 15% (c) 20% (d) 25%

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

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

27. 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

28. 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

29. 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

30. If the interest on 4000 rupees for 4 years is 1600 rupees, then what is the interest rate?

(a) 5% (b) 10% (c) 12\(\cfrac{1}{2}\)% (d) 15%