SOLUTION: 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?

Algebra.Com
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?
------------------
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.)

RELATED QUESTIONS

A nurse has 1 liter of a solution that is 20% alcohol. How much pure alchol must she add... (answered by stanbon)
A nurse has 1 liter of a solution that is 10% alcohol. How much pure alcohol must she add (answered by josmiceli)
The nurse has 2.68 liter(s) of a solution that is 81.8% alcohol. How many liters of pure... (answered by josgarithmetic)
The nurse has 2.68 liter(s) of a solution that is 81.8% alcohol. How many liters of pure... (answered by MathTherapy)
The nurse has 4.25 liters of a solution that is 73% alcohol. How many liters of pure... (answered by stanbon)
The nurse has 1.14 liters of a solution that is 58% alcohol. How many liters of pure... (answered by stanbon)
A nurse has a solution that is 25% alcohol and another that is 50% alcohol. How much if... (answered by stanbon)
Please help me with this problem as I am terrible at math. It comes from a worksheet. A (answered by Nate,stanbon,ankor@dixie-net.com)
How much pure alcohol must a nurse add to 10 cm^3 of a 60% alcohol solution to strengthen (answered by Alan3354,josmiceli)