A sum of money at compound interest doubles in 8 years. In how many years will it become 16 times? MCQ with Answer and Explanation

A sum of money at compound interest doubles in 8 years. In how many years will it become 16 times?

A. 48 years

B. 32 years

C. 40 years

D. 24 years

Answer: Option B

Doubles in 8 years; 16 = 2⁴, so time = 8 × 4 = 32 years.

This question belongs to: Maths Compound Interest

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Question #1 Report Error

A sum of money invested at compound interest doubles itself in 7 years. In how many years will it become 8 times of itself?

A. 35 years

B. 14 years

C. 28 years

D. 21 years

Correct Answer: Option D

Explanation:
The sum doubles (2^1) in 7 years. It will become 8 (2^3) times in 3 * 7 = 21 years.

This question belongs to: Maths Compound Interest

Question #2 Report Error

The difference between simple interest and compound interest on a certain sum of money for 2 years at 10% per annum is Rs. 100. Find the sum.

A. Rs. 11000

B. Rs. 12000

C. Rs. 9000

D. Rs. 10000

Correct Answer: Option D

Explanation:
Difference for 2 years = P * (R/100)^2 => 100 = P * (10/100)^2 => 100 = P * 0.01 => P = Rs. 10000.

This question belongs to: Maths Compound Interest

Question #3 Report Error

A sum of money at compound interest doubles in 4 years. In how many years will it become 8 times?

A. 20 years

B. 12 years

C. 16 years

D. 10 years

Correct Answer: Option B

Explanation:
2 times in 4 years, 8 = 2³ ⇒ 4 × 3 = 12 years.

This question belongs to: Maths Compound Interest