A sum of money placed at compound interest becomes double of itself in 7 years. In how many years will it become 16 times of itself? MCQ with Answer and Explanation

A sum of money placed at compound interest becomes double of itself in 7 years. In how many years will it become 16 times of itself?

A. 42 years

B. 35 years

C. 21 years

D. 28 years

Answer: Option D

The sum becomes 2^1 times in 7 years. It will become 16 (2^4) times in 4 * 7 = 28 years.

This question belongs to: Maths Compound Interest

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Question #1 Report Error

Find the compound interest on Rs. 10800 at 10% per annum for 2 years.

A. Rs. 2268

B. Rs. 2484

C. Rs. 2160

D. Rs. 2376

Correct Answer: Option A

Explanation:
A = 10800 × 1.21 = 13068, CI = 13068 − 10800 = Rs. 2268.

This question belongs to: Maths Compound Interest

Question #2 Report Error

A machine depreciates at 10% per annum. Its present value is Rs. 7290. What was its value 3 years ago?

A. Rs. 10000

B. Rs. 12000

C. Rs. 13000

D. Rs. 11000

Correct Answer: Option A

Explanation:
Value 3 years ago = 7290 / (0.9)³ = 7290 / 0.729 = 10000.

This question belongs to: Maths Compound Interest

Question #3 Report Error

In how many years will Rs. 900 amount to Rs. 1089 at 10% per annum compound interest?

A. 1 year

B. 2 years

C. 1.5 years

D. 2.5 years

Correct Answer: Option B

Explanation:
900(1.1)^t = 1089 ⇒ (1.1)^t = 1.21 ⇒ t = 2.

This question belongs to: Maths Compound Interest