A train 420 m long, running with a speed of 63 km/hr will pass a tree in?\nOptions:\n(A) 36 sec\n(B) 16 sec\n(C) 17 sec\n(D) 88 sec\n(E) 12 sec
Stream of thoughts:
(A)
Speed = 63 * 5/18 = 35/2 m/sec\nTime taken = 420 * 2/35 = 36 sec.

The answer is (A)