If the compound interest on a sum of money for 3 years at the rate of 5% per annum is Rs. 252.20, the simple interest on the same sum at the same rate and for the same time is ?

$$\eqalign{ & {\text{Rate = 5% }} \cr & {\text{Time = 3 years}} \cr & {\text{Compound Interest Rs. 252}}{\text{.20}} \cr & {\text{Effective rate% of CI for 3 years}} \cr & {\text{ = 15}}{\text{.7625% }} \cr & {\text{Effective rate% of SI for 3 years}} \cr & {\text{ = 5}} \times {\text{3 = 15% }} \cr & {\text{Required SI }} \cr & {\text{ = }}\frac{{252.20}}{{15.7625}} \times 15 \cr & = 240 \cr} $$