A train crosses a man standing on a platform in 12 seconds and crosses the platform, which is 150 meters long, in 20 seconds. What is the length of the train?
Show answer & explanation
Correct answer: B
Explanation
Time taken to pass a man = 12 s
Length of the platform = 150 m
Time taken to cross the platform = 20 s
Let the length of the train be x m.
Speed while passing the man = x / 12
Distance covered while crossing the platform = x + 150
Speed = (x + 150) / 20
Both speeds must be equal:
20x = 12(x + 150)
20x = 12x + 1800
8x = 1800
x = 225
Length of the train = 225 m