A train of length 360 metres crosses an electric pole in 30 seconds and crosses another train of the same length travelling in opposite direction in 15 seconds. What is the speed of the second train?

36 m/s

In first case ,

Total distance = 360 m

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

= \(\frac{360}{30}\) = 12 m/sec

Now ,

In 2 nd case

Total distance = 360 + 360 = 720 m

Let speed of another train = x m/sec

Relative speed = (x + 12) m/sec

(When both the trains moves in opposite direction )

Time taken to cross each  other = 15 sec

Relative Speed  = \(\frac{720}{15}\) = 48 m/sec

Now , x + 12 = 48 m/sec

x = 36 m/sec

So ,  speed of second train  = 36 m/sec