A train 800 m long passes a man, running at 15 km/hr in the same direction in which the train is going, in 180 sec. The speed of the train is? Select:  A) 5 km/hr  B) 1 km/hr  C) 2 km/hr  D) 3 km/hr  E) 4 km/hr
Speed of the train relative to man = 800/180 = 40/9 m/sec.   = 40/9 * 18/5= 
<gadget id="calculator">40/9 * 18/5</gadget>
<output>16</output>
16 km/hr   Let the speed of the train be x km/hr. Then, relative speed= (x - 5) km/hr.   x - 15 = 16 =&gt; x = 1 km/hr.   Answer: 1 km/hr
<result>B</result>
A train 800 m long passes a man, running at 15 km/hr in the same direction in which the train is going, in 180 sec. The speed of the train is?