Question 1194698
.
How many quarts of pure alcohol should be added to 10 quarts of 10% alcohol solution 
to obtain a mixture of 25% alcohol?
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<pre>
Initially, we have 10 quarts of 10% acohol solution.


It contains, obviously, 1 quarts of pure alcohol and 10-1 = 9 quarts of water.


When we add pure alcohol, the water contents of 9 quarts remains uncheanged.


So, in the new mixture, 9 quarts of water should comprise 75% of liquid.


Hence, the total volume of the mixture should be  {{{9/0.75}}} = {{{9/((3/4))}}} = 3*4 = 12 quarts.


It means that 12-10 = 2 quarts of the pure alcohol should be added.    <U>ANSWER</U>
</pre>

Solved.


It can be solved in other way/(ways), &nbsp;too, &nbsp;but &nbsp;I &nbsp;presented here the &nbsp;MENTAL &nbsp;solution.


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On solving mixture problems, &nbsp;see the lessons


&nbsp;&nbsp;&nbsp;&nbsp;- <A HREF=http://www.algebra.com/algebra/homework/word/mixtures/Mixture-problems.lesson>Mixture problems</A>

&nbsp;&nbsp;&nbsp;&nbsp;- <A HREF=http://www.algebra.com/algebra/homework/word/mixtures/More-Mixture-problems.lesson>More Mixture problems</A>

&nbsp;&nbsp;&nbsp;&nbsp;- <A HREF=http://www.algebra.com/algebra/homework/word/mixtures/Solving-typical-mixture-problems.lesson>Solving typical word problems on mixtures for solutions</A> 


&nbsp;&nbsp;&nbsp;&nbsp;- <A HREF=https://www.algebra.com/algebra/homework/word/mixtures/Special-type-mixture-problems-on-DILUTION-adding-water.lesson>Special type mixture problems on DILUTION adding water</A>

&nbsp;&nbsp;&nbsp;&nbsp;- <A HREF=https://www.algebra.com/algebra/homework/word/mixtures/Increasing-concentration-of-an-acid-solution-by-adding-pure-acid.lesson>Increasing concentration of an acid solution by adding pure acid</A> 


in this site.



Read them and become an expert in solution the mixture word problems.


Also, you have this free of charge online textbook in ALGEBRA-I in this site

&nbsp;&nbsp;&nbsp;&nbsp;- <A HREF=https://www.algebra.com/algebra/homework/quadratic/lessons/ALGEBRA-I-YOUR-ONLINE-TEXTBOOK.lesson>ALGEBRA-I - YOUR ONLINE TEXTBOOK</A>.


The referred lessons are the part of this online textbook under the topic "<U>Mixture problems</U>".



Save the link to this online textbook together with its description


Free of charge online textbook in ALGEBRA-I
https://www.algebra.com/algebra/homework/quadratic/lessons/ALGEBRA-I-YOUR-ONLINE-TEXTBOOK.lesson


to your archive and use it when it is needed.