Question 482472
Runner A	6	m/s				
Runner B	10	m/s				
Runner A	is ahead 	70	m 	when 	Runner B starts
catch up distance=		70	m 			
catch up speed =		10	-6	mph		
catch up speed =		4	mph			
Catchup time = catchup distance/catch up speed						
catch up time=		70	/	4		
catch up time=		17.5	seconds