Two trains of length 400 m and 200 m are 200 m apart. They start moving towards each other on parallel tracks, at speeds 54 kmph and 36 kmph. After how much time will the trains meet?	Pick one:	A) 8 sec	B) 20/7 sec	C) 33/7 sec	D) 21/7 sec	E) 32/7 sec
They are moving in opposite directions, relative speed is equal to the sum of their speeds.   Relative speed = (54 + 36)*5/18= 
<gadget id="calculator">(54 + 36)*5/18</gadget>
<output>25</output>
25 mps.   The time required= d/s = 200/25= 
<gadget id="calculator">200/25</gadget>
<output>8</output>
8 sec.   8 secnswer : 8 sec
<result>A</result>
Two trains of length 400 m and 200 m are 200 m apart. They start moving towards each other on parallel tracks, at speeds 54 kmph and 36 kmph. After how much time will the trains meet?