## Algebra and Trigonometry 10th Edition

$x+y=500 \\ 0.87 x+0.92 y=445$
Let $x$ and $y$ be the number of gallons of 87-octane gasoline and of 92-octane gasoline, respectively. $x+y=500 \\ 0.87 x+0.92 y=(0.89)(500)$ Therefore, the system of two equations is: $x+y=500 \\ 0.87 x+0.92 y=445$