A train 110 m long travels at 60 km/h. In how many seconds will it completely pass a 240 m long platform?

Difficulty: Easy

Correct Answer: 21 sec

Explanation:

Introduction / Context:Total distance to clear a platform equals train length + platform length. Convert speed to m/s and divide total distance by that speed to get time in seconds.

Given Data / Assumptions:

  • L_train = 110 m; L_platform = 240 m.
  • v = 60 km/h = 16.6667 m/s.

Concept / Approach:S = 110 + 240 = 350 m. Time t = S / v_mps.

Step-by-Step Solution:

v = 60 * 5/18 = 50/3 ≈ 16.6667 m/s.t = 350 / (50/3) = 350 * 3 / 50 = 21 s.

Verification / Alternative check:Dimensional check yields seconds; magnitude aligns with typical moderate-speed trains.

Why Other Options Are Wrong:18, 20, 24, 16 s do not match S/v with correct conversion.

Common Pitfalls:Forgetting to add both lengths; mishandling 60 km/h to m/s conversion.

Final Answer:21 sec

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