SOLUTION: Doreen Schmidt is a chemist. She needs to prepare 36 ounces of a 17​% hydrochloric acid solution. Find the amount of 18​% solution and the amount of 9​% solution she should m

Algebra ->  Customizable Word Problem Solvers  -> Mixtures -> SOLUTION: Doreen Schmidt is a chemist. She needs to prepare 36 ounces of a 17​% hydrochloric acid solution. Find the amount of 18​% solution and the amount of 9​% solution she should m      Log On

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Question 1137196: Doreen Schmidt is a chemist. She needs to prepare 36 ounces of a 17​% hydrochloric acid solution. Find the amount of 18​% solution and the amount of 9​% solution she should mix to get this solution.
Found 2 solutions by josgarithmetic, greenestamps:
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
Variables and arithmetic to start could go like this:

x, how much ounces of 18% HCl
36-x, how much of 9% HCl

18x%2B9%2836-x%29=17%2A36
simplify and solve...

Answer by greenestamps(13200) About Me  (Show Source):
You can put this solution on YOUR website!


You should know the standard algebraic method for solving mixture problems like this, as shown by the other tutor.

But here is a much easier and faster way to solve this problem (and MANY similar problems) with just a bit of mental arithmetic.

The desired 17% concentration is 8/9 of the way from the lower 9% to the higher 18%. That means 8/9 of the mixture must be the higher concentration.

8/9 of 36 ounces is 32 ounces.

ANSWER: 32 ounces of 18%; 4 ounces of 9%.