A train that is 280 metres long, travelling at a uniform speed, crosses a platform in 60 seconds and passes a man standing on the platform in 20 seconds. What is the length of the platform in metres?

GATE 2014 · General Aptitude · Speed Time Distance · medium

Answer: The length of the platform is 560 metres.

1. Find the speed of the train: When passing the man, distance = train length = 280 m, time = 20 s. Speed = 280 / 20 = 14 m/s
2. Find total distance when crossing the platform: When crossing platform: distance = 14 * 60 = 840 m. This distance equals (train length + platform length).
3. Calculate platform length: Platform length = 840 - 280 = 560 m