A train moving at a speed of 63 km/hr enters a railway station and crosses the platform in 20 s. if the length of the train is 100m, what is the length of the platform?

Correct option is C

Let the length of the platform be 'x' m
Train's length = 100 m
Train's speed = 63 km/hr
Train's speed in m/s = 63 × 5/18 = 17.5 m/s
According to the question,
(100 + x)/17.5 = 20
100 + x = 350
x = 250