SOLUTION: The meat department in a grocery store purchased 800 lb of hamburger that is 90% lean beef. How many lbs of hamburger that is 75% lean must be mixed with this 90% lean mix to produ

Question 1041593: The meat department in a grocery store purchased 800 lb of hamburger that is 90% lean beef. How many lbs of hamburger that is 75% lean must be mixed with this 90% lean mix to produce hamburger that is 85% lean beef?
Found 2 solutions by josmiceli, stanbon:
Answer by josmiceli(19441) (Show Source): You can put this solution on YOUR website!
Note that fat is the part that is not lean
pounds of fat in 800 pounds of meat
Let = pounds of hamburger that is 25% fat
that needs to be added
= pounds of fat in 25% fat hamburger
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Notice I switched from lean to fat in each case
( that way I get smaller numbers )

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400 pounds of hamburger that is 75% lean ( 25% fat )
must be added
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check:

OK
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
The meat department in a grocery store purchased 800 lb of hamburger that is 90% lean beef. How many lbs of hamburger that is 75% lean must be mixed with this 90% lean mix to produce hamburger that is 85% lean beef?
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lean + lean = lean
0.90*800 + 0.75x = 0.85(800+x)
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Multiply thru by 100 to get:
90*800 + 75x = 85*800 + 85x
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10x = 5*800
x = 400 lbs (amt. of 75% lean to add)
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Cheers,
Stan H.
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