A sum of money at compound interest doubles in 7 years. In how many years will it become 8 times? MCQ with Answer and Explanation

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

A. 28 years

B. 21 years

C. 14 years

D. 35 years

Answer: Option B

Doubles in 7 years, 8 = 2³, so 7 × 3 = 21 years.

This question belongs to: Maths Compound Interest

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Question #1 Report Error

Find the compound interest on Rs. 1600 at 10% per annum for 2 years if the interest is compounded annually.

A. Rs. 340

B. Rs. 350

C. Rs. 320

D. Rs. 336

Correct Answer: Option D

Explanation:
A = 1600 × (1.1)² = 1600 × 1.21 = 1936, CI = 1936 − 1600 = Rs. 336.

This question belongs to: Maths Compound Interest

Question #2 Report Error

A sum of money amounts to Rs. 4840 in 2 years and Rs. 5324 in 3 years at compound interest. Find the rate.

A. 10%

B. 8%

C. 12%

D. 15%

Correct Answer: Option A

Explanation:
Rate = (5324/4840 − 1) × 100 = (1.1 − 1) × 100 = 10%.

This question belongs to: Maths Compound Interest

Question #3 Report Error

Find the amount on Rs. 12500 at 8% per annum compound interest for 2 years.

A. Rs. 14620

B. Rs. 14580

C. Rs. 14640

D. Rs. 14600

Correct Answer: Option B

Explanation:
A = 12500 × (1.08)² = 12500 × 1.1664 = 14580.

This question belongs to: Maths Compound Interest