SOLUTION: Soybean meal is 14% protein; cornmeal is 7% protein. How many lbs of each should be mixed together in order to get 280-lb mixture that is 10% protein? How many pounds of the corn

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Question 150550: Soybean meal is 14% protein; cornmeal is 7% protein. How many lbs 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 soybean should be in the mixture?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let s = lbs of soybean meal to be used
Let c = lbs of cornmeal to be used
Protein in the soybean meal = .14s
Protein in the cornmeal = .07c
In words:
(total lbs of protein in mixture) / (lbs of mixture) = % protein
%28.14s+%2B+.07c%29+%2F+280+=+.1
multiply both sides by 280
(1) .14s+%2B+.07c+=+28
Also known is s+%2B+c+=+280
Multiply both sides by .14
(2) .14s+%2B+.14c+=+39.2
Subtract (1) from (2)
.07c+=+11.2
c+=+160 lbs
And since s+%2B+c+=+280
s+%2B+160+=+280
s+=+120 lbs
160 lbs of cornmeal are needed and 120 lbs of soybean meal are needed
check:
%28.14s+%2B+.07c%29+%2F+280+=+.1
%28.14%2A120+%2B+.07%2A160%29+%2F+280+=+.1
%2816.8+%2B+11.2%29+%2F+280+=+.1
28+%2F+280+=+.1
28+=+28
OK