Question

A train of length $100\text{m}$ is crossing a bridge $200\text{m}$ long in length at the speed of $72\text{kmph}$. What is the time taken by the train to cross the bridge?

• A. 5 seconds
• B. 10 seconds
• C. 15 seconds
• D. 20 seconds

Answer 1

The correct option is C 15 seconds

Speed of train $=72\text{kmph}=72\times \frac{5}{18}{\text{ms}}^{-1}=20{\text{ms}}^{-1}$

Distance travelled to cross the bridge entirely:
$=(100+200)\text{m}=300\text{m}$

Time taken to cross the bridge:
$=\frac{300\text{m}}{20{\text{ms}}^{-1}}=15\text{second}$