SOLUTION: A chemist wants to make 57 ml of a 17% acid solution by mixing an 11% acid solution and a 20% acid solution. How many milliliters of each solution should the chemist use?

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Question 1148679: A chemist wants to make 57 ml of a 17% acid solution by mixing an 11% acid solution and a 20% acid solution. How many milliliters of each solution should the chemist use?
Found 2 solutions by ikleyn, greenestamps:
Answer by ikleyn(52781) About Me  (Show Source):
You can put this solution on YOUR website!
.
Let x be the volume of the 20% solution, in milliliters;  then the volume of the 11% solution is (57-x) mL.


Your basic equation is


    0.20x+%2B+0.11%2857-x%29 = 0.17*57


saying that the total pure acid volume in the ingredients is equal to the pure acid volume in the mixture.


From the equations,  express x and calculate


    x = %28017%2A57-0.11%2A57%29%2F%280.20-0.11%29 = 38.


ANSWER.  38 mL of the 20% solution and the rest,  57-38 = 19 mL of the 11% solution.


CHECK.  I will check if the concentration is correct.


               Concentration = %280.20%2A38%2B0.11%2A19%29%2F%2838%2B19%29 = 0.17.   ! Precisely correct !

Solved.

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It is a standard and typical mixture problem.

For introductory lessons covering various types of mixture word problems see
    - Mixture problems
    - More Mixture problems
    - Solving typical word problems on mixtures for solutions
    - Typical word problems on mixtures from the archive
in this site.

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

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

Also,  you have this free of charge online textbook in ALGEBRA-I in this site
    - ALGEBRA-I - YOUR ONLINE TEXTBOOK.

The referred lessons are the part of this textbook in the section "Word problems" under the topic "Mixture problems".


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.


Answer by greenestamps(13200) About Me  (Show Source):
You can put this solution on YOUR website!


Here is a quick alternative to the standard algebraic solution method shown by the other tutor (assuming, of course, that an algebraic solution method is not required....)

(1) 17% is 2/3 of the way from 11% to 20%. (Picture the three percentages on a number line -- 11, 17, and 20. 11 to 20 is 9; 11 to 17 is 6; 6 is 2/3 of 9.)

(2) That means 2/3 of the mixture must be the higher percentage ingredient.

ANSWER: 2/3 of 57ml, or 38ml, of the 20% acid solution; the other 19ml of the 11% acid solution.