document.write( "Question 169045: Mr. Key has 50 liters of a 70% ethyl alcohol solution. How many liters of pure ethyl alcohol must be added to obtain an 80% ethyl alcohol solution? How many liters of each solution did he have? I am stumped. Please explain how I put into a chart and how I can get the answer. I appreciate your help. \n" ); document.write( "

Algebra.Com's Answer #124665 by Earlsdon(6294) $\"\"$ $\"About$

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Let x = the number of liters of pure (100%) ethyl alcohol to be added to the 50 liters of 70% ethyl alcohol solution to obtain 50+x liters of 80% ethyl alcohol solution.
\n" ); document.write( "Change the percentages to their decimal equivalents:
\n" ); document.write( "70% = 0.7
\n" ); document.write( "80% = 0.8
\n" ); document.write( "Now you can write the equation to sove for x:
\n" ); document.write( "50(0.7)+x = (50+x)(0.8) Simplify.
\n" ); document.write( "35+x = 40+0.8x Subtract 0.8x from both sides.
\n" ); document.write( "35+0.2x = 40 Subtract 35 from both sides.
\n" ); document.write( "0.2x = 5 Divide both sides by 0.2
\n" ); document.write( "x = 25
\n" ); document.write( "Mr. Key will need to add 25 liters of pure (100%) ethyl alcohol to the 50 liters of 70% alcohol solution to obtain 75 liters of 80% alcohol solution. \n" ); document.write( "

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