Question 564084
Cyclist I	6	mph					
Cyclist II	10	mph					
					
Difference in time=			3	hours		
Cyclist I	will have covered	18	m 	before 	Cyclist II		starts
catch up distance=		18	m 				
catch up speed =		10	-6	mph			
catch up speed =		4	mph				
Catchup time = catchup distance/catch up speed							
catch up time=		18	/	4			
catch up time=		4.5	hours