A train crosses a 100 m platform in 60 seconds at a speed of 45 km/h. How long will it take to cross an electric pole?

Introduction / Context:Crossing a platform yields an equation for (train length + platform length). With speed known, we can derive the train length and then compute the time to cross a pole (distance = train length only).

Given Data / Assumptions:

• Speed v = 45 km/h = 12.5 m/s.
• Platform length = 100 m; platform-cross time = 60 s.

Concept / Approach:(L + 100) = v * 60. Solve for L, then pole-cross time = L / v.

Step-by-Step Solution:L + 100 = 12.5 * 60 = 750 → L = 650 m.Time to cross pole = 650 / 12.5 = 52 s.

Verification / Alternative check:Platform check: (650 + 100)/12.5 = 60 s; consistent.

Why Other Options Are Wrong:8 s and 1 minute conflict with the computed length and speed; “Data inadequate” is incorrect because the given info suffices.

Common Pitfalls:Assuming platform-cross time equals pole-cross time, or forgetting to add platform length.

Final Answer:52 seconds