Question

At what rate per cent compound interest does a sum of money become four fold in $2$ years?

• A. $25$%
• B. $50$%
• C. $100$%
• D. $10$%

Answer 1

The correct option is C $100$%

$4x=x{(1+\frac{r}{100})}^2$
$\because {(1+\frac{r}{100})}^2=4$ or $1+\frac{r}{100}=2$
or $r=100$%