Question 503049
Train A =	20	mph						
Train B = 30 mph	
Train A starts 	2 hours	early				
Train A will have covered	40	miles	before 	Train B starts	from station		
catch up distance=		40	miles							
catch up speed =		30	-20	mph						
catch up speed =		10	mph							
Catchup time = catchup distance/catch up speed										
catch up time=		40	/	10						
catch up time=		4	hours