A train 600 m long passes a man, running at 5 km/hr in the same direction in which the train is going, in 15 seconds. The speed of the train is:
Choose the correct choice from the following options:
A) 45 km/hr  B) 149 km/hr  C) 54 km/hr  D) 55 km/hr  E) 56 km/hr
Speed of the train relative to man = (600/15) m/sec = 40 m/sec. [40 * (18/5)] km/hr = 144 km/hr. Let the speed of the train be x km/hr. Then, relative speed = (x - 5) km/hr. x - 5 = 144 ==&gt; x = 149 km/hr.   ANSWER: 149 km/hr
<result>B</result>
A train 600 m long passes a man, running at 5 km/hr in the same direction in which the train is going, in 15 seconds. The speed of the train is: