What was the question for this implicit rationale, and corresponding answer?
D = 72 * 5/18 = 20 = 400 â€“ 250 = 150m
 The answer: (A)
The question: A train 250 m long running at 72 kmph crosses a platform in 20 sec. What is the length of the platform?
Options:
(A) 150m
(B) 200m
(C) 250m
(D) 270m
(E) 300 m