Question 551647
You have not given how many miles they are apart. I have asssumed 600 miles.
Just plug the distance and get your answer

Automobile I	x 	mph						
Automobile II	x+	10						
..								
They are moving towards each other								
								
So add up their speed.								
								
combined speed = x+x+10			
(2x+10) 			
Time = 	5	hours						
Distance =   	600	miles						
Distance = speed * time							=	
(2x+10	)*5=	600
10	x 	+	50	=	600			
10	x 	=	600	+	-50			
10	x 	=	550					
/	10							
x=	55	mph	Automobile I					
Automobile II	55	+	10	=	65	mph