document.write( "Question 164106: How many kilograms of pure alcohol must be added to 40 kg of a 70% alcohol solution to produce an 85% alcohol solution? \n" ); document.write( "
Algebra.Com's Answer #120983 by alicealc(293)\"\" \"About 
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Let pure alcohol = x kg\r
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\n" ); document.write( "\n" ); document.write( "x + (70/100)*40 = (85/100)*(x + 40)
\n" ); document.write( "<=> x + 0.7*40 = 0.85*(x + 40)
\n" ); document.write( "<=> x + 28 = 0.85x + 34
\n" ); document.write( "<=> x - 0.85x = 34 - 28
\n" ); document.write( "<=> 0.15x = 6
\n" ); document.write( "<=> x = 6/0.15
\n" ); document.write( "<=> x = 40\r
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\n" ); document.write( "\n" ); document.write( "so 40 kg of pure alcohol must be added \r
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