Question

A train running at 54 kmph takes 20 seconds to pass a platform. Next it takes.12 sec to pass a man walking at 6 kmph in the same direction in which the train is going . Find the length of the train and the length of the platform.

Answer 1

Let the length of train be x metres and length of platform be y metres.

Speed of the train relative to man = (54 - 6) kmph = 48 kmph

= 48*(5/18) m/sec = 40/3 m/sec.

In passing a man, the train covers its own length with relative speed.

Length of train = (Relative speed Time) = ( 40/3)12 m = 160 m.

Also, speed of the train = 54 *(5/18)m / sec = 15 m / sec.

(x+y)/15 = 20

x + y = 300

Y = (300 - 160) m

= 140 m.