A 280 m long train is moving at a speed of 40 kmph. How much time will it take to pass a bridge that is 120 m long?

It takes 36 seconds to pass the bridge.

Convert speed: 40 kmph = 40 x 5/18 = 100/9 m/s.

To pass a bridge the train covers its length plus the bridge.

Distance = 280 + 120 = 400 m.

Time = 400 / (100/9) = 400 x 9/100 = 36.

So it takes 36 seconds.