SOLUTION: Hi math enthusiasts, I have been trying to work this linear system word problem and just cannot figure it out. I must be missing something! Please help! In your chemistry cla

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Question 970057: Hi math enthusiasts,
I have been trying to work this linear system word problem and just cannot figure it out. I must be missing something! Please help!
In your chemistry class you have a bottle of 5% boric acid solution and a bottle of 2% boric acid solution. You need 60ml of a 3% boric acid solution for an experiment. How much of each solution do you need to mix together?
I tried to work it like this:
X=5
Y=2
X+Y=60
y= -x+60
5x+2y=3
I got this for the solutions:
X= -20, Y=80
Since x is negative, I know this is not correct. Please show me how to set this up. Thank you
Found 2 solutions by AnlytcPhil, Fombitz:
Answer by AnlytcPhil(1806)   (Show Source): You can put this solution on YOUR website!
Your equation

5x+2y=3  is wrong.

It came from

0.05x+0.2y=0.03  <-- that says (% acid) + (% acid) = %

When you add acid to acid you get acid, not "percent"!

is wrong

It should be

5x+2y=18
which comes from:    

0.05x+0.02y=.03(60)
0.05x+0.02y=1.8  
      5x+2y=18

Now you can finish.

Edwin
Answer by Fombitz(32388)   (Show Source): You can put this solution on YOUR website!
Let X be the amount of 5% solution and Y be the amount of 2% solution.
Total volume equation:

Total concentration equation:


Multiply the first equation by 2 and subtract from the second,



So then,
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