A 200 m long train runs at 60 km/h. How many seconds does it take to pass a man standing still on a platform?

Introduction / Context:When a train passes a stationary point-like observer, the distance to be covered is its own length. Time equals length divided by speed, but speed must be in m/s if length is in metres and time is in seconds. So unit conversion is crucial.

Given Data / Assumptions:

• Train length L = 200 m.
• Speed v = 60 km/h = 60 * (1000/3600) m/s.
• Observer is stationary (relative speed equals the train’s speed).

Concept / Approach:Compute v in m/s, then apply t = L / v. No platform length is involved because the person is a point reference.

Step-by-Step Solution:

Verification / Alternative check:Check with fraction: 60 km/h = 5/3 m/s * 10 = 50/3? No: correctly 60 * (5/18) = 50/3 ≈ 16.666…; 200 * 3 / 50 = 12 s.

Why Other Options Are Wrong:10/15/18 s imply speeds different from 60 km/h for a 200 m train.

Common Pitfalls:Using km/h directly with metres; or mistakenly adding extra distance as if passing a platform.

Final Answer:12 sec