SOLUTION: Soybean meal is 14% protein; cormeal is 7% protein. How many pounds of each should be mixed together in order to get 280-lb mixture that is 11% protein? How many pounds of the

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Question 366493: Soybean meal is 14% protein; cormeal is 7% protein. How many pounds of each should be mixed together in order to get 280-lb mixture that is 11% protein?
How many pounds of the cornmeal should be in the mixture?
How many pounds of the soybean meal should be in the mixture?

Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let c = pounds of cornmeal needed
Let s= pounds of soybean meal needed
given:
Pounds of protein in c pounds of cornmeal:
.07c
Pounds of protein in s pounds of soybean meal
.14s
(1) c+%2B+s+=+280
----------------
In words:
(pounds of protein in final mixture)/(total pounds of final mixture) = 11%
%28.07c+%2B+.14s%29%2F280+=+.11
.07c+%2B+.14s+=+30.8
7c+%2B+14s+=+3080
divide both sides by 7
(2) c+%2B+2s+=+440
Subtract (1) from ()
(2) c+%2B+2s+=+440
(1) -c+-+s+=+-280
s+=+160
and, since
c+%2B+s+=+280
c+=+120
120 pounds of cornmeal and 160 pounds of soybean meal are needed
check answer:
%28.07c+%2B+.14s%29%2F280+=+.11
%28.07%2A120+%2B+.14%2A160%29%2F280+=+.11
%288.4+%2B+22.4%29%2F280+=+.11
8.4+%2B+22.4+=+30.8
30.8+=+30.8
OK