Question

The compound interest on Rs. 20,480 at $6\frac{1}{4}$% per annum for 2 years 73 days, is

• A. $Rs.2929$
• B. $Rs.3000$
• C. $Rs.3131$
• D. $Rs.3636$

Answer 1

The correct option is A $Rs.2929$

Principal$=20480Rs.$

Time $=2years73days=$$2\frac{1}{5}years$

interest rate$\frac{25}{4}\%$

Amounnt after $2years73days=$$20480(1+\frac{25}{4\times 100}{)}^2(1+\frac{\frac{1}{5}\times \frac{25}{4}}{100})$

$\Rightarrow 20480(1+\frac{25}{4\times 100}{)}^2(1+\frac{5}{4\times 100})$

$\Rightarrow 20480(1+\frac{1}{16}{)}^2(1+\frac{1}{80})$

$\Rightarrow 20480(\frac{17}{16}{)}^2\frac{81}{80}$

$\Rightarrow \frac{20480\times 17\times 17\times 81}{16\times 16\times 80}$

$\Rightarrow \frac{256\times 17\times 17\times 81}{16\times 16}$

$\Rightarrow 17\times 17\times 81=23409Rs.$

Then $C.I.=23409-20480=2929Rs.$