Soybean meal is 14% protein, cornmeal is 7% protein. How many pounds of each should be mixed together in order to get 280lbs mixture that is 11% protein?

x - 14%

y - 7 %

x + y = 280

x = 280 -y

.14x + .07y = .11(280)

.14(280-y) + .07y = 30.8

39.2 - .14y + .07y =30.8

.07y = 8.4

y = 120

x =160