A sum doubles in 5 years at compound interest. In how many years will it become 4 times? MCQ with Answer and Explanation

A sum doubles in 5 years at compound interest. In how many years will it become 4 times?

A. 15 years

B. 8 years

C. 10 years

D. 12 years

Answer: Option C

Doubles in 5 years, so quadruple (2²) in 5 × 2 = 10 years.

This question belongs to: Maths Compound Interest

No comments yet. Be the first to start the discussion!

Question #1 Report Error

The simple interest on a sum for 3 years at 12% is Rs. 432. The compound interest on the same sum for 2 years at 12% is:

A. Rs. 303.36

B. Rs. 305.28

C. Rs. 300

D. Rs. 310

Correct Answer: Option B

Explanation:
P = 43200/(12×3) = 43200/36 = 1200. CI = 1200[(1.12)² − 1] = 1200 × 0.2544 = 305.28.

This question belongs to: Maths Compound Interest

Question #2 Report Error

The effective annual rate for 24% per annum compounded half-yearly is:

A. 25.44%

B. 26.50%

C. 26%

D. 25%

Correct Answer: Option A

Explanation:
Half-yearly rate 12%, (1.12)² = 1.2544, effective = 25.44%.

This question belongs to: Maths Compound Interest

Question #3 Report Error

The effective annual rate for 7% per annum compounded half-yearly is:

A. 7.25%

B. 7.10%

C. 7.12%

D. 7.20%

Correct Answer: Option C

Explanation:
Half-yearly rate 3.5%, (1.035)² = 1.071225, effective = 7.1225% ≈ 7.12%.

This question belongs to: Maths Compound Interest