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Let x be the volume of the 65% solution to mix.
Then the volume of the 15% solution is (70-x) liters.
The volume of the pure acid in 65% solution is 0.65x liters..
The volume of the pure acid in 15% solution is 0.15*(70-x) liters.
The volume of acid solution in the final mixture is the sum of that in ingredients.
It gives you this equation
0.65x + 0.15*(70-x) = 0.30*70.
From the equation, express x and calculate
x = = 21 liter.
ANSWER. 21 liter of the 65% solution, and the rest, 70-21 = 49 liters of the 15% solution.
CHECK. 0.65*21 + 0.15*49 = 21 liter of the pure acid = 0.30*70. ! Precisely correct !
Solved.
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It is a standard and typical mixture problem.
In this site, there is a bunch of lessons, covering various types of mixture problems. See introductory lessons
- Mixture problems
- More Mixture problems
- Solving typical word problems on mixtures for solutions
- Word problems on mixtures for antifreeze solutions
- Word problems on mixtures for alloys
- Typical word problems on mixtures from the archive
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
- ALGEBRA-I - YOUR ONLINE TEXTBOOK.
The referred lessons are the part of this online textbook 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.