Question 422314
Lucas speed	5	kph			
father's rate	8	kph			
					
Difference in time=	7.5 hours	(15/2) hours	
Lucas  will have covered 37.5 km	father starts	
					
catch up distance=37.5	km		
catch up speed =	8-5 kph	
catch up speed =	3 kph		
					
Catchup time = catchup distance/catch up speed					
catch up time=37.5/3	
catch up time= 12.5 hours