A train passes a station platform in 50 sec and a man standing on the platform in 20 sec. If the speed of the train is 54 km/hr. What is the length of the platform?  Answers.
A) 615 m  B) 240 m  C) 168 m  D) 300 m  E) 691 m

Rationale: speed = 54 * 5 / 18 = 15 m / sec . length of the train = 15 * 20 = 300 m . let the length of the platform be x m . then , ( x + 300 ) / 50 = 15 = > x = 300 m answer : d
Answer: D