*The difference *between *the compound interest *and *simple interest *on a *certain sum *at 10% *per *annum *for *2 *years is Rs. *631. *Find the sum.*

53,100

52,900

63,100

64,500

C. 63,100

Let the sum be Rs. x. Then,

C.I. = x ( 1 + ( 10 /100 ))^{2 }- x = 21x / 100 ,

S.I. = (( x * 10 * 2) / 100) = x / 5

(C.I) - (S.I) = ((21x / 100 ) - (x / 5 )) = x / 100

( x / 100 ) = 632 , x = 63100.

Hence, the sum is Rs.63,100.