Question

A $60m$ long train moving on a straight level track passes a pole in $5s,$ find the speed of the train and the time it will take to cross a $540m$ long bridge.

• A. 13 m/s, 40 s
• B. 25 m/s, 30s
• C. 12 m/s, 50s
• D. 15 m/s, 65 s

Answer 1

The correct option is C

12 m/s, 50s

Speed of the train $=\frac{\text{Length of the train}}{\text{Time taken to cross the pole}}$
$=\frac{60}{5}m/s$
$=12m/s$

Now, distance to be covered to cross a $540m$ long bridge:
$=$ Length of the train $+$ Length of the bridge
$=60+540=600m$

Hence, time taken $=\frac{\text{distance}}{\text{speed}}$
$=\frac{600}{12}=50s$