By using the formula, find the amount and compound interest on:
Rs 10240 for 3 years at $12 \frac{1}{2} \%$ per annum compounded annually.
Principal amount, $P=$ Rs 62500
Rate of interest, $R=12 \%$ p. a.
Time, $n=2$ years 6 months $=\frac{5}{2}=2 \frac{1}{2}$ years
The formula for the amount including the compound interest is given below :
$A=$ Rs. $P\left(1+\frac{R}{100}\right)^{\mathrm{n}}$
$\Rightarrow A=$ Rs. $62500\left(1+\frac{12}{100}\right)^{2} \times\left(1+\frac{\frac{1}{2} \times 12}{100}\right)$
$\Rightarrow A=$ Rs. $62500\left(1+\frac{12}{100}\right)^{2} \times\left(1+\frac{6}{100}\right)$
$\Rightarrow A=$ Rs. $62500 \times 1.12 \times 1.12 \times 1.06$
$\Rightarrow A=$ Rs. 83104
i.e., the amount including the compound interest is Rs $83104 .$
$\therefore$ Compound interest $=$ Rs. $(83104-62500)=$ Rs. 20604