A train 130 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?  Choices
A) 13 km/hr B) 51.8 km/hr C) 17 km/hr D) 18 km/hr E) 12 km/hr
Speed of the train relative to man = (130/10) m/sec   = (13) m/sec. [(25/2) * (18/5)] km/hr   = 46.8 km/hr. Let the speed of the train be x km/hr. Then, relative speed   = (x - 5) km/hr. x - 5 = 46.8 ==&gt; x   = 51.8 km/hr.   Answer:51.8 km/hr
<result>B</result>
A train 130 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?