A train 50m long takes 6 sec to cross a man walking at 5kmph in a direction opposite to that of the train. Find the speed of the train?  Choose the correct option.
A) 15 kmph B) 25 kmph C) 35 kmph D) 45 kmph E) 55 kmph

Rationale: "let the speed of the train be x kmph speed of the train relative to man = x + 5 = ( x + 5 ) * 5 / 18 m / sec 50 / [ ( x + 5 ) * 5 / 18 ] = 6 30 ( x + 5 ) = 900 x = 25 kmph answer is b"
Answer: B