A sum amounts to Rs.3087 in 2 years at the rate of 5% p.a. If interest was compounded yearly then what was the principal?
Choose the correct choice from the following.
A) s . 4000 B) s . 5000 C) s . 4500 D) s . 4800 E) s . 2800

Rationale: "ci = 3087 , r = 5 , n = 2 ci = p [ 1 + r / 100 ] ^ 2 = p [ 1 + 5 / 100 ] ^ 2 3087 = p [ 21 / 20 ] ^ 2 3087 [ 20 / 21 ] ^ 2 2800 answer : e"
Answer: E