SOLUTION: A pharmacist needs 70 liters of a 50% alcohol solution. She has available a 30% solution and a 80% solution. How many liters of each solution should she mix to obtain what she

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Question 726142:
A pharmacist needs 70 liters of a 50% alcohol solution. She has available a 30% solution and a 80% solution. How many liters of each solution should she mix to obtain what she needs?

Answer by checkley79(3341) About Me  (Show Source):
You can put this solution on YOUR website!
.80X+.30(70-X)=.5*70
.80X+21-.30X=35
.50X=35-21
.50X=14
X=14/.5
X=28 L. OF 80% SOLUTION IS USED.
70-28=42 L. OF 20% SOLUTION IS USED.
PROOF:
.80*28+.30*42=.5*70
22.4+12.6=35
35=35