Two trains of length 100 m and 200 m are 100 m apart. They start moving towards each other on parallel tracks, at speeds 24 kmph and 48 kmph. After how much time will the trains meet?  Pick:
A) 20/8 sec
B) 20/4 sec
C) 20/7 sec
D) 22/7 sec
E) 5 sec
They are moving in opposite directions, relative speed is equal to the sum of their speeds.   Relative speed = (24 + 48)*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>E</result>
Two trains of length 100 m and 200 m are 100 m apart. They start moving towards each other on parallel tracks, at speeds 24 kmph and 48 kmph. After how much time will the trains meet?