A person borrows Rs.5000 for 2 years at 4% p.a. simple interest. He immediately lends it to another person at 7% p.a for 2 years. Find his gain in the transaction per year. Choose the correct choice from the following choices:
A) 167.5  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 7 % p . a for 2 years simple interest that he gets = prt / 100 = 5000 × 7 × 2 / 100 = 700 his overall gain in 2 years = rs . 700 - rs . 400 = rs . 300 his overall gain in 1 year = 300 / 2 = rs . 150 answer : option b"
Answer: B