A sum of money invested at compound interest doubles itself in 15 years. In how many years will it become 4 times of itself? MCQ with Answer and Explanation

A sum of money invested at compound interest doubles itself in 15 years. In how many years will it become 4 times of itself?

A. 45 years

B. 30 years

C. 60 years

D. 20 years

Answer: Option B

The sum doubles (2^1) in 15 years. It will become 4 (2^2) times in 2 * 15 = 30 years.

This question belongs to: Maths Compound Interest

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Question #1 Report Error

The simple interest on a sum for 2 years at 6% is Rs. 480. The compound interest on the same sum for 2 years at 6% is:

A. Rs. 508.80

B. Rs. 499.20

C. Rs. 504.00

D. Rs. 494.40

Correct Answer: Option D

Explanation:
P = 48000/(6×2) = 4000. CI = 4000[(1.06)² − 1] = 4000 × 0.1236 = Rs. 494.40.

This question belongs to: Maths Compound Interest

Question #2 Report Error

The effective annual rate of interest for 12% per annum compounded quarterly is:

A. 12.60%

B. 12.55%

C. 12.65%

D. 12.50%

Correct Answer: Option B

Explanation:
Quarterly rate = 3%, (1.03)⁴ = 1.12550881, effective ≈ 12.55%.

This question belongs to: Maths Compound Interest

Question #3 Report Error

A sum of money at compound interest becomes Rs. 8820 in 2 years and Rs. 9261 in 3 years. Find the rate.

A. 3%

B. 4%

C. 6%

D. 5%

Correct Answer: Option D

Explanation:
Rate = (9261/8820 − 1) × 100 = (1.05 − 1)×100 = 5%.

This question belongs to: Maths Compound Interest