Multiple choice

A train running at 30 km/hr takes 24 seconds to cross a platform. It takes 8 seconds to pass a man walking towards it at 6 km/hr. Find the length of the platform.

  1. 110 m.

  2. 120 m.

  3. 135 m.

  4. 160 m.

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Train speed = 30 km/h = 30×(5/18) = 25/3 m/s. Time to pass man = 8 seconds. Relative speed (man walking towards train) = 30 + 6 = 36 km/h = 36×(5/18) = 10 m/s. Train length = 10 × 8 = 80 m. Time to cross platform = 24 seconds. Total distance = train length + platform length = 25/3 × 24 = 200 m. Platform length = 200 - 80 = 120 m.