A sum of money invested at compound interest doubles itself in 16 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 16 years. In how many years will it become 4 times of itself?

A. 24 years

B. 48 years

C. 32 years

D. 40 years

Answer: Option C

The sum doubles (2^1) in 16 years. It will become 4 (2^2) times in 2 * 16 = 32 years.

This question belongs to: Maths Compound Interest

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Question #1 Report Error

A sum of money amounts to Rs. 12960 in 2 years and Rs. 15552 in 3 years at compound interest. Find the sum.

A. Rs. 9000

B. Rs. 9500

C. Rs. 8500

D. Rs. 8000

Correct Answer: Option A

Explanation:
Rate = (15552/12960 − 1) × 100 = 20%. P = 12960 / 1.44 = 9000.

This question belongs to: Maths Compound Interest

Question #2 Report Error

At what rate of compound interest will Rs. 625 amount to Rs. 676 in 2 years?

A. 6%

B. 5%

C. 4%

D. 3%

Correct Answer: Option C

Explanation:
625(1 + r)² = 676 ⇒ (1+r)² = 1.0816 = (1.04)² ⇒ r = 4%.

This question belongs to: Maths Compound Interest

Question #3 Report Error

At what rate will Rs. 8000 amount to Rs. 9261 in 3 years at compound interest?

A. 8%

B. 5%

C. 4%

D. 6%

Correct Answer: Option B

Explanation:
8000(1+r)³ = 9261 ⇒ (1+r)³ = 1.157625 = (1.05)³ ⇒ r = 5%.

This question belongs to: Maths Compound Interest