Solution :
Let the sum be Rs. P, then
$$
\begin{array}{c}
\text { Amount, } P\left(1+\frac{R}{100}\right)^{t}=67600 \\
\Rightarrow P\left(1+\frac{4}{100}\right)^{2}=67600 \\
\Rightarrow P\left(\frac{26}{25}\right)^{2}=67600 \\
\Rightarrow P \times \frac{676}{625}=67600 \\
\therefore P=\frac{67600 \times 625}{676} \\
=62500 \text {; Ans. }
\end{array}
$$