Question

At what rate % will a sum of money double itself in $16$ years?

• A. $50$%
• B. $5$%
• C. $\frac{25}{4}$%
• D. none of these

Answer 1

Answer: (C)

$\frac{25}{4}$%

The money doubles itself, it means $100\%$ money is added.

So,

Interest $\times$ Time $=100\%$

Interest $\times 16=100$

Interest $=\frac{100}{16}$

Interest $=\frac{25}{4}$

So the simple interest is $\frac{25}{4}\%$ per year.