SOLUTION: I need help with this no one can seem to help me: Doreen Schmidt is a chemist with Gemco Pharmaceutical. She needs to prepare 12 ounces of a 9% hydrochloric acid solution. Find th

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Question 303516: I need help with this no one can seem to help me:
Doreen Schmidt is a chemist with Gemco Pharmaceutical. She needs to prepare 12 ounces of a 9% hydrochloric acid solution. Find the amount of a 4% solution and the amount of a 12% solution she should mix to get this solution.
The answer I got was 12%=3.75 and 4%=8.25... Am I remotely correct?
Janna
Found 2 solutions by richwmiller, scott8148:
Answer by richwmiller(17219) About Me  (Show Source):
You can put this solution on YOUR website!
You are close but not close enough to pass.
12*.09=.04x+.12y
x+y=12

Answer by scott8148(6628) About Me  (Show Source):
You can put this solution on YOUR website!
no, not remotely

if you mixed equal amounts of the two solutions; the strength of the resulting mixture would be the average
___ in this case, 12 ounces of 8%
___ so the stronger solution must be more than half of the mixture

(4%)(x) + (12%)(12 - x) = (9%)(12)

4x + 144 - 12x = 108

36 = 8x

4.5 = x

4.5 oz of 4% and 7.5 oz of 12%