SOLUTION: Karen is working in the chemistry lab and needs a solution that is 8% hydrochloric acid. She has two solutions that she can mix together to get the solution of the required strengt

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Question 158855: Karen is working in the chemistry lab and needs a solution that is 8% hydrochloric acid. She has two solutions that she can mix together to get the solution of the required strength. The first solution is 2% hydrochloric acid, and the other is 11% hydrochloric acid. How many kilograms of each solution should she mix to produce four kilograms of the required strength.
Answer by nerdybill(7384) About Me  (Show Source):
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Karen is working in the chemistry lab and needs a solution that is 8% hydrochloric acid. She has two solutions that she can mix together to get the solution of the required strength. The first solution is 2% hydrochloric acid, and the other is 11% hydrochloric acid. How many kilograms of each solution should she mix to produce four kilograms of the required strength.
.
Let x = amt of 2% hydrochloric acid
then
4-x = amt of 11% hydrochloric acid
.
"amt of acid from 2%" + "amt of acid from 11%" = "amt of acid desired"
translating the above into an equation from our variables:
.02x + .11(4-x) = .08(4)
Solving then:
.02x + .44 - .11x = 0.32
.44 - .09x = 0.32
.44 = .09x + 0.32
0.12 = .09x
1.33 kilograms = x (amount of 2% hydrochloric acid)
.
11% hydrochloric acid:
4-x = 4-1.33 = 2.67 kilograms (amount of 11% hydrochloric acid)