<PRE><B>Question 448873</B>
Soybean meal is 14% protein, cornmeal is 7% protein.
 How many pounds of each should be mixed together in order to get 280-lb mixture that is 13% protein.
 How many pounds of cornmeal? How many pounds of soybean?
:
Let x = amt of soy
the states that the resulting total will equal 280 lb, therefore
(280-x) = amt of cornmeal
:
Write a per-cent protein equation in decimal form:
:
.14x + .07(280-x) = .13(280)
.14x + 19.6 - .07x = 36.4
.14x - .07x = 36.4 - 19.6
.07x = 16.8
x = {{{16.8/.07}}}
x = 240 lb of soy
then
280 - 240 = 40 lb of corn meal
:
:
Check this
.14(240) + .07(40) =
33.6 + 2.8 = 36.4</PRE>