Expert: Scott A Wilson - 9/25/2011

Question
Soybean meal is 20% protein, cornmeal is 6% protein, How many pounds of each should mix together in order get 240lb. mixture that is 9% protein?

Answer
Soybean is 20% and cornmeal is 6%, and we want a total of 9% out of 240 lb.
That means if we use x pounds of soybean, we use 240 - x pounds of cornmeal.

For protein, that give us the equation 0.20x + 0.06(240-x) = 0.09(240).
That works out to 0.20x + 14.4 - 0.06x = 21.6.
That simplifies to 0.14x = 7.2.

That works out to x = 355/7 = 50 5/7.

I noticed that if I had 420 total pounds, it came out to an integer answer.