The difference between compound interest and simple interest on a certain amount of money at 5% per annum for 2 years is 16. Find the sum :	Answers:  A) 4500  B) 7500  C) 5000  D) 6400  E) none of these

Rationale: "sol . ( d ) let the sum be 100 . therefore , si = 100 × 5 × 2 / 100 = 10 and ci = 100 ( 1 + 5 / 100 ) 2 − 100 ∴ = 100 × 21 × 21 / 20 × 20 − 100 = 41 / 4 difference of ci and si = 41 ⁄ 4 - 10 = 1 ⁄ 4 if the difference is 1 ⁄ 4 , the sum = 100 = > if the difference is 16 , the sum = 400 × 16 = 6400 answer d"
Answer: D