Question

A train passes a station platform in 36 seconds and a man standing on the platform in20 seconds. If the speed of the train is 54 km/hr, what is the length of the platform

Answer 1

54 km/hr = 15m/s

when the train passes a man it means it covered a distance equal to the length of that train

speed=distance/time

distance(here the length of the train) = speed x time

length = 15 x 20 = 300m

therefore the length of the train is 300m

when the train passes a platform it means it covered a distance equal to  (length of that train + length of the platfrom)

speed=distance/time ( here distance is length of that train + length of the platfrom)

15 = (300+d)/36  (d= length of the platform)

d = (15 x 36) - 300

d = 540 - 300

d = 240m

therefore the length of the platform is 240 m