Question

The SI on a sum of money for $3$ years is Rs. $24$ and the CI on the sum at the same rate for $2$ years is Rs. $17$. The rate % p.a. is:

• A. $12.25$
• B. $12.5$
• C. $11.25$
• D. $12.75$

Answer 1

The correct option is B $12.5$

$SI=\frac{P\times r\times t}{100}$

$24=\frac{P\times r\times 3}{100}$

$P=800/r$

$CI=P\left[\right(1+\frac{r}{100}{)}^n-1]$

$17=\left(800/r\right)\left[\right(1+\frac{r}{100}{)}^2-1]$

Solving for we get, $r\approx 12.5$.