A train crosses a pole in 12 sec, and a bridge of length 170 m in 36 sec. Then the speed of the train is:

25.5 km/h

A trains crossed a pole i.e. its length in 12 sec .

And trains crosses 170m bridge in 36 sec . That means time taken by train to cover 170 m distance = 36 - 12 = 24 sec

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

= \(\frac{170 }{24}\) m/sec

\(\frac{170 }{24}\) × \(\frac{18 }{5}\) = 25.5 km/h

So , speed of train is 22.5 km/h