Two trains each 200m long are moving in opposite directions. They cross each other in 10 seconds. If the speed of one train is 90km/h, find the speed of the other train.

54 km/h

Speed = \(\frac{Distance}{Time}\)

When moves in opposite direction , Relative speed is difference of speed of both

Total distance to cover = 200 + 200 = 400 m

Speed= \(\frac{400}{10}\) = 40 m/sec

Speed of 1st train = 90 km/h = 25 sec

Let speed of another train = A m/sec

So ,

( 25 - A ) = 40

A = 15 m/sec

15 m/sec = 15 × \(\frac{18}{5}\) km/h = 54 km/h

So , Speed of another train is 54 km/h