A sum becomes Rs. 2916 in 2 years at 8% per annum compound interest. The simple interest at 9% per annum for 3 years on the same amount will be = ?

$$\eqalign{ & {\text{Amount = Rs}}{\text{. 2916}} \cr & {\text{Time = 2 years }} \cr & {\text{Rate = 8}}\% \cr & {\text{Effective rate }}\% {\text{ CI for 2 years}} \cr & {\text{ = 8 + 8 + }}\frac{{8 \times 8}}{{100}} = 16.64\% \cr & {\text{Required sum}} \cr & {\text{ = }}\frac{{2916}}{{\left( {100 + 16.64} \right)}} \times 100 \cr & = {\text{Rs}}{\text{. }}2500 \cr & {\text{Required simple interest}} \cr & {\text{ = }}\frac{{2500 \times 9 \times 3}}{{100}} \cr & = {\text{Rs}}{\text{. }}675 \cr} $$