A train crosses a platform of 120 m in 15 sec, same train crosses another platform of length 250 m in 20 sec. then find the length of the train?
Choose the correct choice from the following answers:
A) 150 m  B) 270 m  C) 180 m  D) 158 m  E) 350 m

Rationale: "length of the train be ‘ x ’ x + 120 / 15 = x + 250 / 20 4 x + 480 = 3 x + 750 x = 270 m answer : b"
Answer: B