Question 154720This question is from textbook college algebra ninth edition
: A nurse has 1 liter of a solution that is 20% alcohol. How much pure alcohol must she add to bring the solution up to a 25% concentration?
This question is from textbook college algebra ninth edition
Answer by Alan3354(69443)   (Show Source):
You can put this solution on YOUR website! A nurse has 1 liter of a solution that is 20% alcohol. How much pure alcohol must she add to bring the solution up to a 25% concentration?
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The 1000 cc of solution is 20% alcohol and 80% water, or 200 cc alcohol and 800 cc water.
She wants it to be 1 part in 4 of alcohol and 3 parts of 4 of water, so it will be 3 times as much water as alcohol. 1/3 of 800 is 266.67, so she must add 66.67 cc of alcohol.
To check:
266.67/1066.67 = 1/4 = 25%
(If she has to work this out, she might drink most of it.)
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