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

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

2. If a principal amount doubles in 10 years, what is the annual simple interest rate?

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

3. If a principal amount doubles in 10 years, the annual simple interest rate will be 20%.

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

(a) 8% (b) 10% (c) 6% (d) 5%

5. If a principal amount doubles in 10 years, what is the annual simple interest rate?

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

6. If a principal amount doubles in 10 years, what is the annual simple interest rate?

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

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

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

8. 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

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

10. If a principal amount doubles in \(x\) years, the annual simple interest rate is -.

11. Rokeya takes a loan from the bank under the condition that she will pay interest at an annual simple interest rate of 10% and repay \(\frac{1}{5}\) of the principal every two years. If she pays 10,000 currency units as the first installment after two years, determine the amount she borrowed.

12. Bimal Kaku deposited 56,000 INR in a bank for his two sons, aged 13 and 15 years, in such a way that when they turn 18, the simple interest earned at an annual rate of 10% on each deposit equals the respective principal amount. Determine how much he deposited in each son's name.

13. If the annual simple interest rate increases from 4% to 5%, causing a person's income to rise by ₹1000, then the person's principal amount is _____.

(a) ₹ 4000 (b) ₹ 5000 (c) ₹ 10000 (d) ₹ 50000

14. If the annual simple interest rate increases from 4% to 5%, causing a person's income to rise by ₹1000, then the person's principal amount is _____.

(a) ₹ 4000 (b) ₹ 5000 (c) ₹ 10000 (d) ₹ 50000

15. If a principal amount doubles in **10 years**, the annual **simple interest rate** is -

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

16. 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?

17. If a principal amount doubles in x years, what is the annual simple interest rate?

18. If a principal amount doubles in 10 years, the annual interest rate will be _____.

19. If ₹800 is deposited in a bank at an annual simple interest rate of 10%, and the total amount received (principal + interest) is ₹1200, then calculate and write for how long the money was deposited in the bank.

20. If the difference between the compound interest and simple interest on a certain amount for 3 years at an annual interest rate of 10% is ₹930, then calculate and write that principal amount.

21. 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.

22. 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

23. 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

24. 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

25. If a principal amount doubles in 4 years, the annual interest rate will be –

(a) 8% (b) 12\(\dfrac{1}{2}\)% (c) 15% (d) 10%

26. If the time period and the annual simple interest rate are equal, then at what annual interest rate will the interest amount be \(\cfrac{1}{25}\) of the principal?

(a) 25% (b) 10% (c) 2% (d) 2.5%

27. 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%

28. If a certain principal amount triples in 15 years at simple interest, then the annual rate of simple interest will be —

(a) \(13\frac{1}{3}\%\) (b) \(12\frac{1}{3}\%\) (c) \(11\frac{1}{3}\%\) (d) \(10\frac{1}{3}\%\)

29. Uday Babu lent a certain amount of money to one person at an annual simple interest rate of 4% for 4 years, and twice that amount to another person at an annual simple interest rate of 10% for the same duration. He received ₹960 more interest from the second person than from the first. Find the total amount of money Uday Babu lent.

30. 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?