The first thing we are going to do for this case is define variables.
We have then:
x: Amount of soybean meal
320 - x: quantity of cornmeal
We now write the equation that models the problem:
[tex]0.16x + 0.08 (320-x) = 0.09 (320)
[/tex]
Rewriting we have:
[tex]0.16x + 25.6 - 0.08x = 28.8
[/tex]
From here, we clear x:
[tex]0.16x - 0.08x = 28.8 - 25.6
0.08x = 3.2
x = 3.2 / 0.08
x = 40[/tex]
Then, the amount of Soybean meal is:
[tex]x = 40 lb
[/tex]
The amount of cornmeal is:
[tex]320 - x = 320 - 40 = 280 lb
[/tex]
Answer:
cornmeal: 280 lb
Soybean: 40 lb.