Train crossing a platform – computing time A train 280 m long moves at 60 km/h. How many seconds are required to cross a platform 220 m long?

Introduction / Context:
This is a direct application of distance = speed * time, with total distance equal to train length plus platform length and careful unit conversion from km/h to m/s.

Given Data / Assumptions:

• Train length = 280 m.
• Platform length = 220 m.
• Speed = 60 km/h.

Concept / Approach:
Convert speed and compute time using total distance.

Step-by-Step Solution:

Verification / Alternative check:
16.666... m/s * 30 s = 500 m, which equals the combined lengths.

Why Other Options Are Wrong:
20 s, 25 s, 35 s: Each gives the wrong travel distance at the given speed. Only 30 s is exact.

Common Pitfalls:
Forgetting to add both lengths or rounding 16.666... too early. Keep exact fraction 50/3 when possible.

Final Answer:
30 sec