A train 540 m long crosses a bridge 390 m long in 30 seconds. What is the speed of the train (in km/hr)?
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → 111.6
To cross a bridge completely, the train covers its own length plus the length of the bridge. A speed in m/s is changed to km/hr by multiplying by \(\frac{18}{5}\).
Distance \(=540+390=930\) m
Speed \(\displaystyle =\frac{930}{30}=31\) m/s
In km/hr: \(\displaystyle 31\times\frac{18}{5}=111.6\) km/hr