<PRE><B>Question 896963</B>
C = A+6
256 miles / 8 hours = 32mph (combined)
A + C = 32
Substitute the value of C from the top equation into the bottom
A + C = 32
A + (A+6) = 32
2A + 6 = 32
Subtract 6 from each side
2A = 26
Divide each side by 2
A = 13
If Andrew travels 13mph, Casey travels 13=6, or 19 mph
In 8 hours, Andrew will have traveled 8*13=104 miles
In 8 hours, Casey will have traveled 19*8=152 miles
104 miles + 152 miles = 256 miles</PRE>