Question 1137340
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<pre>

Let x be the required amount (volume) of the 20% acid solution (in milliliters).


Then the equation for the pure acid volume is 


    0.2x + 0.40*50 = 0.25*(x + 50).


It is your basic equation for this problem. 

Simplify it


    0.2x - 0.25x = 0.25*50 - 0.4*50


Express x from the equation and calculate the answer


    x = {{{(0.25*50- 0.4*50)/(0.2 - 0.25)}}} = 150.


<U>Answer</U>. 150 milliliters.


<U>CHECK</U>.  (0.20*150 + 0.40*50)/(50 + 150)}}} = 0.25,  or 25%.    ! Correct !
</pre>

Solved.


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It is a standard and typical mixture problem.


In this site, there is a huge collection of lessons covering various types of mixture word problems. 
Start from these introductory 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/Typical-word-problems-on-mixtures-from-the-archive.lesson>Typical word problems on mixtures from the archive</A>


You will find there ALL TYPICAL mixture problems with different methods of solutions,
explained at different levels of detalization, &nbsp;from very detailed to very short.


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


Also, &nbsp;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 textbook in the section "<U>Word problems</U>" 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.