How much time will a train of length 200 m moving at a speed of 72 kmph take to cross another train of length 300 m, moving at 36 kmph in the same direction?  Choose the correct choice from the following
A) 50 sec	B) 26 sec	C) 80 sec	D) 82 sec	E) 81 sec

Rationale: the distance to be covered = sum of their lengths = 200 + 300 = 500 m . relative speed = 72 - 36 = 36 kmph = 36 * 5 / 18 = 10 mps . time required = d / s = 500 / 10 = 50 sec . answer : a
Answer: A