A train running at 26.5 km/h takes 18 s to pass a platform. Next, it takes 12 s to pass a man walking at 5 km/h in the opposite direction. Find the length of the platform.
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 27.5 m.
Train's speed = 26.5 km/h
Man's speed = 5 km/h
Relative speed = 26.5 + 5 = 31.5 km/h = 31.5 × (5/18) m/sec = 35/4 m/sec
Train's length = (35/4) × 12 = 105 meters
Distance = Train's speed × Time taken to pass the platform
= 26.5 × (5/18) × 18 = 132.5 meters
Platform's length = 132.5 - 105 = 27.5 meters
Therefore, the length of the platform is 27.5 meters.