A person borrows Rs.5000 for 2 years at 4% p.a. simple interest. He immediately lends it to another person at 6% p.a for 2 years. Find his gain in the transaction per year.
Choose the correct choice from the following options.
A) 100  B) 150  C) 225  D) 112.5  E) 212.5

Rationale: "explanation : the person borrows rs . 5000 for 2 years at 4 % p . a . simple interest simple interest that he needs to pay = prt / 100 = 5000 × 4 × 2 / 100 = 400 he also lends it at 6 % p . a for 2 years simple interest that he gets = prt / 100 = 5000 × 6 × 2 / 100 = 600 his overall gain in 2 years = rs . 600 - rs . 400 = rs . 200 his overall gain in 1 year = 200 / 2 = rs . 100 answer : option a"
Answer: A