SOLUTION: Nicolas mixes three solutions of acid with concentrations of 10%, 15%, and 5%. He wants to make 30 L of a mixture that is 12% acid and he uses four times as much of the 15% solutio

Question 1055238: Nicolas mixes three solutions of acid with concentrations of 10%, 15%, and 5%. He wants to make 30 L of a mixture that is 12% acid and he uses four times as much of the 15% solution as the 5% solution. How much each of the three solutions must he use?
Found 2 solutions by josgarithmetic, MathTherapy:
Answer by josgarithmetic(39620) (Show Source): You can put this solution on YOUR website!
Three-part mixture but you can turn this into something that looks like a two-part mixture problem.

VOLUME CONCENTRATION x 5% y 10% z 15%

Already an equation is identified.

and again, you know one already found equation, useful as .

If you think carefully for a few seconds, you can continue this partly through Elimination Method.

( x=6 )
Answer by MathTherapy(10552) (Show Source): You can put this solution on YOUR website!

Nicolas mixes three solutions of acid with concentrations of 10%, 15%, and 5%. He wants to make 30 L of a mixture that is 12% acid and he uses four times as much of the 15% solution as the 5% solution. How much each of the three solutions must he use?

Correct answers:
Again, IGNORE THE OTHER PERSON'S USUAL ERRONEOUS solution, if it can be called a solution!
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