Question 723809
Train I	60	mph				
Train II	90	mph				
Train I		06:00				
Train II		06:45				
Difference in time=		00:45	=>	.75	hours	
Train I	will have covered	45.00	miles		Train II	starts
catch up distance=		45.00	miles			
catch up speed =		90	-60			
catch up speed =		30	mph			
Catchup time = catchup distance/catch up speed						
catch up time=		1.5				
catch up time=		1.50	hours	= 90 minutes