A train 400 m long passes a man, running at 7 km/hr in the same direction in which the train is going, in 30 sec. The speed of the train is?	Pick.
A) 39 km/hr
B) 40 km/hr
C) 41 km/hr
D) 42 km/hr
E) 43 km/hr
Speed of the train relative to man = 400/30 = 40/3 m/sec.   = 40/3 * 18/5= 
<gadget id="calculator">40/3 * 18/5</gadget>
<output>48</output>
48 km/hr   Let the speed of the train be x km/hr. Then, relative speed= (x - 5) km/hr.   x - 7 = 48 =&gt; x = 41 km/hr.   Answer: 41 km/hr
<result>C</result>
A train 400 m long passes a man, running at 7 km/hr in the same direction in which the train is going, in 30 sec. The speed of the train is?