If difference between compound interest and simple interest on a sum at 5% P.a. for 2 years is Rs.60, then what is the sum?  Options:
A) rs . 8000  B) rs . 4000  C) rs . 5000  D) rs . 6000  E) rs . 24000

Rationale: "c . i - s . i = 60 si = ( x * 2 * 5 ) / 100 = x / 10 ci = { x * ( 1 + 5 / 100 ) ^ 2 - x } = 41 x / 400 ci - si = 41 x / 400 - x / 10 = 60 x = 24000 answer : e"
Answer: E