Two trains of length 350 m and 250 m are 100 m apart. They start moving towards each other on parallel tracks, at speeds 36 kmph and 36 kmph. After how much time will the trains meet?
Select
A) 27/7 sec  B) 20/7 sec  C) 5 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 = (36 + 36)*5/18 = 4*5= 
<gadget id="calculator">4*5</gadget>
<output>20</output>
20 mps.   The time required= d/s = 100/20= 
<gadget id="calculator">100/20</gadget>
<output>5</output>
5 sec.   Answer : 5 sec
<result>C</result>
Two trains of length 350 m and 250 m are 100 m apart. They start moving towards each other on parallel tracks, at speeds 36 kmph and 36 kmph. After how much time will the trains meet?