A train 145 m long passes a man, running at 5 km/hr in the same direction in which the train is going, in 10 seconds. The speed of the train is?  Choose the correct choice from the following options:  A) 13 km/hr  B) 57.2 km/hr  C) 17 km/hr  D) 18 km/hr  E) 12 km/hr
Speed of the train relative to man = (145/10) m/sec   = (14.5) m/sec. [(14.5) * (18/5)] km/hr   = 52.2 km/hr. Let the speed of the train be x km/hr. Then, relative speed   = (x - 5) km/hr. x - 5 = 52.2 ==&gt; x   = 57.2 km/hr.   Answer:57.2 km/hr
<result>B</result>
A train 145 m long passes a man, running at 5 km/hr in the same direction in which the train is going, in 10 seconds. The speed of the train is?