A train crosses a pole in 12 seconds and a bridge of length 170 meters in 36 seconds. Then the speed of the train is?
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → 25.50 km/hr
To cross a pole the train covers its own length; to cross a bridge it covers its own length plus the bridge. So the extra time taken on the bridge is the time to cover the 170 m of the bridge alone.
Extra time: \(36-12=24\) seconds for 170 m
Speed: \(\displaystyle\frac{170}{24}\) m/s
In km/hr (multiply by \(\frac{18}{5}\)): \(\displaystyle\frac{170}{24}\times\frac{18}{5}=25.5\) km/hr