Trains Q25

25.A train  100 metres 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.?

A.150 Kmph                                              B.55kmph

C.15 Kmph                                                 D.120 Kmph

Sol: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 100/((x+5)*5/18)=6 <=> 30 (x + 5) = 1800 <=> x = 55

Speed of the train is 55 kmph.