Two trains of length 100 m and 200 m are 100 m apart. They start moving towards each other on parallel tracks, at speeds 54 kmph and 72 kmph. In how much time will the trains cross each other?
Pick one.
A) 100/7 sec B) 80/7 sec C) 57/7 sec D) 120/7 sec E) 50/7 sec
Relative speed = (54 + 72)* 5/18 = 7 * 5= 
<gadget id="calculator">7 * 5</gadget>
<output>35</output>
35 mps.   The time required= d/s = (100 + 100 + 300)/35   = 500/35 = 100/7 sec.   100/7 secNSWER:100/7 sec
<result>A</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 54 kmph and 72 kmph. In how much time will the trains cross each other?