SOLUTION: 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 10% protein? How many pounds of the co

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Question 329365: 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 10% protein?
How many pounds of the cornmeal should be in the mixture?
How many pounds of the soybean should be in the mixture?

Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
In words:
(pounds of protein in final mixture)/(pounds of final mixture) = 10%
-------------------
Let c = pounds of cornmeal in final mixture
Let s = pounds of soybean meal in final mixture
given:
.14s = pounds of protein in soybean meal
.07c = pounds of protein in corn meal
(1) s+%2B+c+=+280
-------------------
%28.14s+%2B+.07c%29%2F280+=+.1
.14s+%2B+.07c+=+28
(2) 14s+%2B+7c+=+2800
Multiply both sides of (1) by 7 and
subtract from (2)
(2) 14s+%2B+7c+=+2800
(1) -7s+-+7c+=+1960
7s+=+840
s+=+120
And, since
(1) s+%2B+c+=+280
120+%2B+c+=+280
c+=+160
160 pounds of cornmeal and
120 pounds of soybean meal are needed
check:
%28.14s+%2B+.07c%29%2F280+=+.1
%28.14%2A120+%2B+.07%2A160%29%2F280+=+.1
%2816.8+%2B+11.2%29%2F280+=+.1
28%2F280+=+.1
.1+=+.1
OK