document.write( "Question 519867: how many ounces of 40% acid and 80% acid must be mixed together to get 160ounces of a 70% acid \n" ); document.write( "

Algebra.Com's Answer #345819 by oberobic(2304) $\"\"$ $\"About$

You can put this solution on YOUR website!
The first rule is to keep track of how much pure stuff you need.
\n" ); document.write( "160 oz of 70% acid would have 160*.7 = 112 oz. of pure acid.
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\n" ); document.write( "x = oz of 40% acid to mix
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\n" ); document.write( "y = oz of 80% acid to mix
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\n" ); document.write( "x+y = 160
\n" ); document.write( "so
\n" ); document.write( "y = 160-x
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\n" ); document.write( ".4(x) + .8(160-x) = 112
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\n" ); document.write( "Multiply by 10 to eliminate decimals.
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\n" ); document.write( "4x +8(160-x) = 1120
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\n" ); document.write( "4x +1280 -8x = 1120
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\n" ); document.write( "-4x = -160
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\n" ); document.write( "x = 40
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\n" ); document.write( "y = 160-x
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\n" ); document.write( "y = 120
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\n" ); document.write( "Answer: 40 oz of 40% acid + 120 oz of 70% solution
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\n" ); document.write( "Check to see if this answer produces the right quantity of pure stuff in the solution.
\n" ); document.write( ".4*40 + .8*120 = 112 oz
\n" ); document.write( "Correct.
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\n" ); document.write( "Done. \n" ); document.write( "

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