<PRE><B>Question 446063</B>
Car I	x 	mph						
Car II	x+	15						
..								
They are going away from each other.								
								
So add up their speed.								
								
combined speed = x+x+15			
(2x+15) 			
Time = 	3	hours						
Distance =   	315	miles						
Distance = speed * time								
(2x+15)*3=315
6x+45=315			
6x=315+-45			
6x=270					
/6							
x=45	mph	Car I					
Car II	45+15=60 mph		
								
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