A train running at the speed of 45 kmph took 12 seconds

A train running at the speed of 45 kmph took 12 seconds in passing a certain point. Then the length of the train must be ?

∵ Speed = (45 x 5/18) = (25/2) m/sec
Distance = (Time x Speed) = (12 x 25 / 2 ) meters
= 150 meters

∴ Length of the train = 150 meters