A man in a train travelling at 28km/hr notices that a train going in the opposite direction passes him in 12 sec.If the length of this train is 210m find its speed .	Choose the correct option.
A) 35 km/hr  B) 40 km/hr  C) 50 km/hr  D) 60 km/hr  E) 70 km/hr
relative speed of trains = 210/12 mtrs/sec = 210*18/(12*5)= 
<gadget id="calculator">210*18/(12*5)</gadget>
<output>63</output>
63 km/hr   speed of 2nd train= 63-28= 
<gadget id="calculator">63-28</gadget>
<output>35</output>
35 km/hr   35 km/hrNSWER:35 km/hr
<result>A</result>
A man in a train travelling at 28km/hr notices that a train going in the opposite direction passes him in 12 sec.If the length of this train is 210m find its speed .