arithmetic - a train 125 m long passes a man running at 5 kmhr in the same direction in which the train is going in 10 seconds the speed of the train is - skillgun

Speed of the train relative to man = 125/10 m/sec
= 25/2 m/sec.
= 25/2 x 18/5 km/hr
= 45 km/hr.
Let the speed of the train be x km/hr. Then, relative speed = (x - 5) km/hr.
x - 5 = 45 x = 50 km/hr.