A train travelling at 48 kmph completely crosses another train having half its length and travelling in opposite direction at 42 kmph, in 12 seconds. It also passes a railway platform in 45 seconds. The length of the platform is Select:	A) 400 m	B) 450 m	C) 560 m	D) 600 m	E) 680 m
Length of the Ist train=2x m and the length of the other train be x m(1/2)   The relative speed of the train (48+42)= 
<gadget id="calculator"> (48+42)</gadget>
<output>90</output>
90kmph or 25m/s   Time taken to cross one another=12s   Hence, 12=2x+x/25   Solving, x=100m and 200m   Now to determine the length of the platform   45=100+length of the platform/speed of the Ist train   45=100+L/240/18( 48kmph=240/118m/s)   Solving, we get L=600M   ANSWER:600 m
<result>D</result>
A train travelling at 48 kmph completely crosses another train having half its length and travelling in opposite direction at 42 kmph, in 12 seconds. It also passes a railway platform in 45 seconds. The length of the platform is