SOLUTION: Soybean meal is 12% protein; cornmeal is 6% protein.? How many pounds of each should be mixed together in order to get a 240-lb mixture that is 80% protein?

You can put this solution on YOUR website!
*** note: there is no way you can get 80% protein from
the mixture. I changed it to 8%, which I think is
what you meant ***
Let = pounds of soybean meal needed
Let = pounds of cornmeal needed
= pounds of protein in soybean meal
= pounds of protein in cornmeal
----------------
(1)
(2)
--------------------------
(2)
(2)
(2)
Subtract (1) from (2)
(2)
(1)

and, since
(1)
(1)
(1)
80 pounds of soybean meal is needed
160 pounds of cornmeal is needed
check:
(2)
(2)
(2)
(2)
OK