Let the weight of soymeal be s, and let the weight of cornmeal be c.
You need a total of 280 lb, so that gives us one equation.
s + c = 280
Now we use the protein to write another equation.
The protein in s lb of soymeal is 0.14s.
The protein in c lb of cornmeal is 0.07c.
The protein in 280 lb of 0.09% protein mix is 0.09(280).
This gives us a second equation.
0.14s + 0.07c = 0.09(280)
Now we solve the two equations as a system of equations.
s + c = 280
0.14s + 0.07c = 0.09(280)
Solve the first equation for s and plug in tot eh second equation.
s = 280 - c
0.14(280 - c) + 0.07c = 25.2
39.2 - 0.14c + 0.07c = 25.2
-0.07c = -14
c = 200
Now we substitute c = 200 in the first equation to find s.
s + 200 = 280
s = 80
Answer: 200 lb of soymeal and 80 lb of cornmeal
