Question

A train $100\text{m}$ long is moving at a speed of $90\text{kmph}$. How long will it take to cross two poles that are $150\text{m}$ apart?

• A. $10\text{min}$
• B. $10\text{s}$
• C. $4\text{s}$
• D. $4\text{min}$

Answer 1

The correct option is B $10\text{s}$


Total distance to be travelled by train to completely cross the poles = distance between the poles + length of the train.

$\text{d}=150+100=250\text{m}$
speed of the train,
$v=90\text{kmph}=90\times \frac{5}{18}=25{\text{m s}}^{-1}$
Time taken,
$\text{t}=\frac{\text{d}}{v}=\frac{250}{25}=10\text{s}$