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.

Explanation

Given: 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. Concept used: Relative speed is the sum of their individual speeds while two bodies are coming from the opposite direction. 1m/s = 18/5 km/h Time × Speed = Distance Calculation: Total distance = 26.5 × 5/18 × 18 = 132.5 m Hence, the relative speed of the train and the person ⇒ 26.5 + 5 = 31.5 km/hr Length of train = 31.5 × 5/18 × 12 ⇒ 105 m Thus, the length of the platform = 132.5 - 105 = 27.5 m ∴ The length of the platform is 27.5 m.