A man has $Rs. 7000$ to invest he invest $Rs. 4000$ at $3 \%$ P.a . At what rate of interest must be invest the remainder in order to obtain $4\%$ interest on the total sum ?

Question

$\begin{array}{1 1} 5\% p.a \\ 5 \frac{1}{3}\%p.a \\ 5 \frac{1}{2}\%p.a \\ 6\% \end{array} $