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_______?

A. Rs.600
B. Rs.500
C. Rs.400
D. Rs.300
Explanation:
Sum be Rs.100
S.I = Rs.(1000/100) =Rs.10
C.I = Rs.[{100 × (1 +5/100) 2} – 100] =Rs.41/4
Difference C.I amd S. I = Rs.(41/4 – 10) =Rs.25
25 : 1.50 : : 100 : x
Therefore x = ((1.50 ×100)/25) = Rs.600