Question

A man earns an interest of ₹510 on a sum he lent at 17% per annum for two years. Had he earned 10% more interest on the same amount in same time , what should be the rate of interest?

• A. 18%
• B. 18.3%
• C. 18.7%
• D. 19%

Answer 1

The correct option is C 18.7%

S.I = ₹510

$\because$ S.I = $\frac{P\times R\times T}{100}$

$\Rightarrow$ P = $\frac{S.I\times 100}{R\times T}$

$\Rightarrow$ P = $\frac{510\times 100}{17\times 2}$

$\Rightarrow$ P = ₹1,500

If, interest is 10% more
$\Rightarrow$ S.I = 510 + 10% of 510
$\Rightarrow$ S.I = ₹561

$\therefore$ R = $\frac{S.I\times 100}{P\times T}$

$\Rightarrow$ R = $\frac{561\times 100}{1,500\times 2}$

$\Rightarrow$ R = 18.7 %

The rate of interest should be 18.7%.