If Greg buys 3 shirts, 4 trousers and 2 ties, the total cost is $40. If Greg buys 7 shirts, 2 trousers and 2 ties, the total cost is $60. How much will it cost him to buy 3 trousers, 5 shirts and 2 ties?
Choose the correct option.
A) $ 50  B) $ 64  C) $ 75  D) $ 96  E) can not be determined

Rationale: "solution : 3 x + 4 y + 2 z = 40 7 x + 2 y + 2 z = 60 adding both the equations = 10 x + 6 y + 4 z = 100 5 x + 3 y + 2 z = 50 ans a"
Answer: A