At what rate of compound interest per annum will a sum of money double in 14 years?

A4%

B5% ✓ Correct

C6%

D6.5%

Correct answer: (B) 5%

Explanation

The rate is about 5% per annum.

Use the doubling approximation 72 / rate = years.

Here 72 / rate = 14.

Rate = 72 / 14 = 5.14.

The closest listed value is 5%.

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