Question

A train crosses a platform 200 m long in 36 seconds and a pole in 18 seconds. Find the speed of the train.

• A. 20 m/s
• B. 15 m/s
• C. 25 m/s
• D. 10 m/s

Hint:

When a train crosses a pole, it covers its own length. When it crosses a platform, it covers its own length plus platform length.

Answer 1

The Correct Option is A

Let the speed of the train be \( v \, \text{m/s} \)
Time to cross a pole \(= 18 \text{ sec} \implies\) Length of train \(= 18v\)
Time to cross a platform \(= 36 \text{ sec} \implies\) Total distance \(= 36v\)
Also, \( \text{Total distance} = \text{Length of train} + \text{Length of platform} = 18v + 200 \) \[ 36v = 18v + 200 \Rightarrow 18v = 200 \Rightarrow v = \frac{200}{18} \approx 11.11 \text{ m/s} \] Note: Nearest option is 10 m/s.