document.write( "Question 1064823: Dr. Alvarado is a chemist. She needs to mix 10 liters of a solution of a certain chemical that is 64% pure. (That is, 64% is the chemical, and the rest is water.) To do this, she will mix a solution that is 70% pure with one that is 50% pure. How many liters of each should she use? \n" ); document.write( "
Algebra.Com's Answer #679913 by rothauserc(4718)\"\" \"About 
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let x be the number of liters of the 70% solution
\n" ); document.write( "let y be the number of liters of the 50% solution
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\n" ); document.write( "1) x + y = 10
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\n" ); document.write( "2) 0.70x + 0.50y = 0.64 * 10 = 6.4
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\n" ); document.write( "solve equation 1 for x
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\n" ); document.write( "x = 10 - y
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\n" ); document.write( "substitute for x in equation 2
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\n" ); document.write( "0.70 * (10 - y) + 0.50y = 6.4
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\n" ); document.write( "7 - 0.70y + 0.50y = 6.4
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\n" ); document.write( "-0.20y = -0.60
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\n" ); document.write( "y = 3
\n" ); document.write( "x = 7
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\n" ); document.write( "Dr. Alvarado mixes 7 liters of the 70% pure and
\n" ); document.write( "3 liters of the 50% pure
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