A train of length 300 metres crosses a tree in 20 seconds and crosses another train of the same length travelling in opposite direction in 25 seconds. What is the speed of the second train?

9 m/s

A trains crossed a tree i.e. its length in 20 sec .

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

=   \(\frac{300 }{20}\) = 15 m/sec

1st train crosses another train of same length moving in opposite direction in 25 sec

Let speed of 2nd train is X km/h

Relative speed = X + 15

Total distance = 300 + 300 = 600 m

Speed = \(\frac{600 }{25}\)

= 24m/sec

Now ,

X + 15 = 24

X = 9 m/sec

So , Speed of 2nd train is 9 m/sec