A sum of money at compound interest doubles itself in 15 years. In how many years will it become eight times itself?

A45 years ✓ Correct

B48 years

C54 years

D60 years

Correct answer: (A) 45 years

Explanation

It becomes eight times in 45 years.

Eight times means 2^3, that is doubling three times.

The sum doubles once in 15 years.

Three doublings need 3 x 15 years.

3 x 15 = 45 years.

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