If a sum of money double itself in 8 years, then the interest rate in percentage is ?
A. $8 \frac{1}{2} \%$ B. $10 \%$ C. $10 \frac{1}{2} \%$ D. $12 \frac{1}{2} \%$ Answer: Option DShow Answer
Solution(By Apex Team)
Money is double itself means interest is equal to money.
$\begin{array}{l}
\mathrm{P}=\frac{\mathrm{P} \times 8 \times \mathrm{r}}{100} \\
\Rightarrow \mathrm{r}=\frac{100}{8} \\
\Rightarrow \mathrm{r}=12 \frac{1}{2} \%
\end{array}$
