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 90 kmph. In how much time will the trains cross each other? Select:	A) 11	B) 10	C) 12	D) 13	E) 14
Relative speed = (54 + 90)* 5/18 = 7 * 5 = 40 mps.   The time required = d/s = (100 + 100 + 200)/40   = 400/40= 
<gadget id="calculator">400/40</gadget>
<output>10</output>
10 sec.   Answer: 10
<result>B</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 90 kmph. In how much time will the trains cross each other?