The length of the bridge, which a train 130 meters long and travelling at 46.8 km/hr can cross in 30 seconds, is:

Question: The length of the bridge, which a train 130 meters long and travelling at 46.8 km/hr can cross in 30 seconds, is:

Solution:
Let,
The length of the bridge is x meter

∴ The train has to travel 130 + x meter to cross the bridge.

The velocity of the train 46.8 km/hr
= (46.8 × 1000)/3600 m/s
= 13 m/s

The train travels in 1 second 13 meters
∴ The train travels in 30 seconds (13 × 30) meters
= 390 meters

Now,
130 + x = 390
⇒ x = 390 - 130
∴ x = 260

∴The length of the bridge is 260 meters