Question

a 100 m long train crosses a 400m bridge with a velocity of 72km/h. calculate the time taken to cross yhe bridge.

Answer 1

Distance = 400 +  100  = 500m 
Speed = 72 km/hr = 72 X 5/18 = 20m/s

Time = Distance/speed = 500m/20m/s = 25s

It 25 second

Answer 2

Total Distance = (100 + 400) m =500 m
Speed = 72 km/h = 20 m/s

Therefore, time = Distance / Speed
= (500 / 20) s
= 25s

Ans. The time taken yo cross the bridge is 25 seconds.