Question

A train of length 150m takes 10s to pass over another train 100m long coming from opposite direction. If the speed of the first train is 30km/h, then what is the speed of the second train ?

Answer 1

Suppose the speed of the second train=x km/h

When two moving objects are running at opposite directions, the relative speed is always sum of their speeds.

And distance /relative speed=Time taken
Here distance is the sum of length of both trains.

=(0.150+0.100)km /(x+30)=10/3600 hours

0.250km /(x+30)=1/360

x+30=90

x=90-30=60km/h