Question 423681
Train A speed	100	mph		
Train B speed	104	mph		
				
Train A passes station at 06:10		
Train B passes station at	 06:40		
				
Difference in time=00:30		
Train A will have covered 50 miles before Train B starts
catch up distance= 50	miles	
catch up speed =	104-100	mph
catch up speed =	4 mph	
				
Catchup time = catchup distance/catch up speed				
catch up time=	50/4
catch up time=	12.5	hours