SOLUTION: A druggist needs 20 oz of a 20% Phenobarital solution, but he only has a 5% solution and a 25% solution in stock. How many ounces of each available solution would he need to ma

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Question 722703:
A druggist needs 20 oz of a 20% Phenobarital solution, but he only has a 5% solution and a 25% solution in stock. How many ounces of each available solution would he need to make the 20% solution he needs?
Answer by checkley79(3341) About Me  (Show Source):
You can put this solution on YOUR website!
.25X+.05(20-X)=.20*20
.25X+1-.05X=4
.20X=4-1
.20X=3
X=3/.20
X=15 OZ. OF THE 25% SOLUTION IS USED.
20-15=5 OZ. OF THE 5% SOLUTION IS USED.
PROOF:
.25*15+.05*5=.20*20
3.75+.25=4
4=4