Question

Q18. A train covers a distance
of 90 km in 90 minutes.. Find
the time taken by the train to
cross an electric pole if the
length of the train is 300m.​

Answer 1

Let the length of the bridge be x metres and length of the first train at 90 km/hr be y metres

Then (x+y)=[(90×

18

5

)×36] m =900 m

The second train crosses the bridge by covering distance of [x+(y−100)]m at the rate of 45 km/hr

12.5 m/s i.e. 800 m at 12.5 m/s (∵x+y=900 m)

Time taken by the second train to cross the bridge =

12.5

800

sec =64 seconds