A sum of money placed at compound interest becomes double of itself in 3 years. In how many years will it become 8 times of itself? MCQ with Answer and Explanation

A sum of money placed at compound interest becomes double of itself in 3 years. In how many years will it become 8 times of itself?

A. 12 years

B. 9 years

C. 15 years

D. 6 years

Answer: Option B

The sum becomes 2^1 times in 3 years. It will become 8 (2^3) times in 3 * 3 = 9 years.

This question belongs to: Maths Compound Interest

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Question #1 Report Error

At what rate percent compound interest will Rs. 2400 amount to Rs. 2646 in 2 years?

A. 7%

B. 6%

C. 5%

D. 4%

Correct Answer: Option C

Explanation:
2400(1+r)² = 2646 ⇒ (1+r)² = 1.1025 ⇒ r = 5%.

This question belongs to: Maths Compound Interest

Question #2 Report Error

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

A. Rs. 9000

B. Rs. 8000

C. Rs. 11000

D. Rs. 10000

Correct Answer: Option A

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

This question belongs to: Maths Compound Interest

Question #3 Report Error

Find the principal if the compound interest on it for 2 years at 10% per annum is Rs. 525.

A. Rs. 2500

B. Rs. 2400

C. Rs. 2700

D. Rs. 2600

Correct Answer: Option A

Explanation:
CI = P[(1.1)² − 1] = P × 0.21 = 525 ⇒ P = 525/0.21 = Rs. 2500.

This question belongs to: Maths Compound Interest