Question

A sum of money is put on CI for 2 years at 20%. It would fetch Rs 482 more if the interest is payable half yearly than if it were payable yearly. Find the sum.

• A. Rs 2000000.
• B. Rs 200000.
• C. Rs 20000.
• D. Rs 2000.

Answer 1

The correct option is C Rs 20000.

Let the sum be $x$

$\Rightarrow x{(1+\frac{10}{100})}^4-x{(1+\frac{20}{100})}^2=482$

$\Rightarrow x{(1+\frac{1}{10})}^4-x{(1+\frac{2}{10})}^2=482$

$\Rightarrow x{\left(\frac{11}{10}\right)}^4-x{\left(\frac{12}{10}\right)}^2=482$

$\Rightarrow x{\left(1.1\right)}^4-x{\left(1.2\right)}^2=482$

$\Rightarrow x\left(1.4641\right)-x\left(1.44\right)=482$

$\Rightarrow x(1.4641-1.44)=482$

$\Rightarrow x\left(0.0241\right)=482$

$\Rightarrow x=\frac{482}{0.0241}=Rs.20,000$