Solution-
Here, $P=$ Rs. $2000, R=10 \%$
t=2 years, C.I= ?
$\therefore \quad$ C.I. $=P \times\left\{\left(1+\frac{R}{100}\right)^{t}-1\right\}$
$=2000 \times\left\{\left(1+\frac{10}{100}\right)^{2}-1\right\}$
$=2000 \times\left\{\frac{121-100}{100}\right\}$
$=2000 \times \frac{21}{100}$
$=\mathrm{Rs}, 420$ : Ans.
Therefore, C.I is Rs.420