A train 150 meters long takes 6 seconds to cross a man walking at 5 kmph in the direction opposite to that of the train. Find the speed of the train.	Choose the correct choice
A) 45 kmph	B) 50 kmph	C) 85 kmph	D) 60 kmph	E) 70 kmph

Rationale: "explanation : let the speed of the train be x kmph . speed of the train relative to man = ( x + 5 ) kmph = ( x + 5 ) × 5 / 18 m / sec . therefore 150 / ( ( x + 5 ) × 5 / 18 ) = 6 < = > 30 ( x + 5 ) = 2700 < = > x = 85 speed of the train is 85 kmph . answer : option c"
Answer: C