document.write( "Question 806217: You need 390 mL of a 80% alcohol solution. On hand, you have a 70% alcohol mixture. How much of the 70% alcohol mixture and pure alcohol will you need to obtain the desired solution?
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Algebra.Com's Answer #485731 by richwmiller(17219)\"\" \"About 
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x+y=390,
\n" ); document.write( ".7x+y=.8*390
\n" ); document.write( "x=260, y=130
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\n" ); document.write( ".7*260+130=.8*390
\n" ); document.write( ".7*260+130=312
\n" ); document.write( "182+130=312
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\n" ); document.write( "\n" ); document.write( "Let A denote the 100% solution and B denote the 70% solution which we have.
\n" ); document.write( "Let C denote the 80% solution which we want.
\n" ); document.write( "Using the method of alligation.
\n" ); document.write( "10= 80 - 70
\n" ); document.write( "20= 100 - 80
\n" ); document.write( "E.g. There are 10 parts of A plus 20 parts of B
\n" ); document.write( "Then 10+20=30
\n" ); document.write( "0.33333333*390=130
\n" ); document.write( "130 mL of 100% solution.\r
\n" ); document.write( "\n" ); document.write( "390-130=260
\n" ); document.write( "260 mL of 70% solution.
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\n" ); document.write( "0.7 * 260 + 1 * 130 = 0.8*390
\n" ); document.write( "182.0 + 130 = 312.0
\n" ); document.write( "312.0 = 312.0
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