SOLUTION: A pharmacist has 20L of a 10% drug solution. How many liters of 5% solution must be added to get a mixture that is 8%?

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Question 181716This question is from textbook Beginning Algebra
: A pharmacist has 20L of a 10% drug solution. How many liters of 5% solution must be added to get a mixture that is 8%? This question is from textbook Beginning Algebra

Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
A pharmacist has 20L of a 10% drug solution. How many liters of 5% solution must be added to get a mixture that is 8%?
:
Let x = amt of 5% solution required
:
Using the decimal equiv, write a mixture equation:
:
.05x + .10(20) = .08(x+20)
:
.05x + 2 = .08x + 1.6
:
2 - 1.6 = .08x - .05x
:
.4 = .03x
x = .4%2F.03
x = 131%2F3 L of 5% solution required
;
:
Check answer:
.05(13.33) + .10(20) = .08(13.33+20)
.67 + 2 = .08(33.33)
2.67 = 2.67