The difference between the compound interest and the simple interest on a certain sum at 5% per annum for 2 years is Rs. 1.50. The sum is?

Let the sum be Rs . 100 then
S.I. = Rs.(100 x 5 x 2/100)= Rs. 10
C.I = Rs. [{100 x (1 + 5/100)²} - 100] = Rs. 41/4
∴ Difference between C.I and S.I = Rs. (41/4 - 10) = Re. 0.25
⇒ 0.25 : 150 : : 100 : P
∴ P = (1.50 x 100) / 0.25 = Rs. 600