Question

a train running at the speed of 120km/hr crosses a pole in 12 seconds.what is the length of the train?

Answer 1

Given the speed of the train = 120km/h
Time taken to cross a pole = 12 sec = 12/60 minutes
                                            = 1/5 min = (1/5)/60 hrs
                                            = 1/300 hrs   
Length of the train = distance covered to cross the pole
Distance = speed × time 
               = 120 ×1/300
               = 120/300
               =  4/10
               =  0.4 km
∴Distance = Length of the train = 0.4 km  
                                                   = 400m
∴ Length of the train = 400m