In what time will a train, 125 m long, moving at a speed of 45 kilometres per hour, cross a bridge 265 metres long ?

Now, the speed of the train is 45 Km per hour.

That is, the train covers 45 Km in 1 hour (= 60 minutes).

1 Km = 1000 metres

So, the train covers (45 x 1000) metres in 60 minutes.

therefore, the train covers 1 metre in 60 / (45 x 1000) minutes.

So the train covers 390 metres in 60 x 390 / (45 x 1000) = 52 /100 minutes.

1 minute = 60 seconds.

By multiplying minutes by 60 we gets seconds.

So 52/100 minutes = 52 x 60 / 100 seconds = 312/ 10 seconds = 31.2 seconds.

**Solution:**To cross a bridge, a train has to travel a distance equal to the sum of its own length and the length of the bridge. So here the train will have to travel (125 m + 265 m) = 390 m.Now, the speed of the train is 45 Km per hour.

That is, the train covers 45 Km in 1 hour (= 60 minutes).

1 Km = 1000 metres

So, the train covers (45 x 1000) metres in 60 minutes.

therefore, the train covers 1 metre in 60 / (45 x 1000) minutes.

So the train covers 390 metres in 60 x 390 / (45 x 1000) = 52 /100 minutes.

1 minute = 60 seconds.

By multiplying minutes by 60 we gets seconds.

So 52/100 minutes = 52 x 60 / 100 seconds = 312/ 10 seconds = 31.2 seconds.

**Answer:**The train crosses the bridge in**31.2 seconds.**