A 400 m long train passes a railway platform in 20 seconds with speed 90 km/hr. What is the length of platform?
Answer & explanation
Correct answer: option 4
Let the length of platform = x m
Length of train = 400 m.
Speed of train = 90 kmph = 90 × \(\frac{5}{18}\) m/sec = 25 m/sec.
Time = 20 sec
Distance traveled by train to cross the platform = Length of train + length of platform = 400 + x
Hence,
Distance = Speed × Time
400 + x = 25 × 20 = 500
x = 100 m