If 180 meter long train crosses a pole in 9 seconds, find the speed of train in kilo meter/hour.

72 km/h

Note: When a train cross a pole, then the distance traveled by the train is always equals to the length of the train.

Now, according to the question:

Length of the train = 180 m

It means, distance traveled by the train to cross the pole = 180m

Time taken by the train = 9 sec.

Speed of train = \(\frac{distance}{time}\) = \(\frac{180}{9}\) = 20m/sec

⇒ 20 m/sec = 20 × \(\frac{18}{5}\) km/hr = 72 km/hr