An woman sitting in a train which is travelling at 20 kmph observes that a goods train travelling in a opposite direction, takes 15 seconds to pass him. If the goods train is 300 m long, find its speed.	Choices:
A) 52 B) 54 C) 56 D) 58 E) 60

Rationale: relative speed = ( 300 / 15 ) m / s = ( 300 / 15 ) * ( 18 / 5 ) = 72 kmph speed of goods train = 72 - 20 = 52 kmph answer is a
Answer: A