document.write( "Question 757087: If you wish to increase the percentage of acid in 50 mL of a 15% acid solution to 25% acid, how much pure acid must you add? \n" ); document.write( "

Algebra.Com's Answer #460631 by josmiceli(19441) $\"\"$ $\"About$

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Let $\"+x+\"$ = ml of acid to be added
\n" ); document.write( " $\"+.15%2A50+=+7.5+\"$ ml of acid in 15% solution
\n" ); document.write( "----------------
\n" ); document.write( " $\"+%28+7.5+%2B+x+%29+%2F+%28+50+%2B+x+%29+=+.25+\"$
\n" ); document.write( " $\"+7.5+%2B+x+=+.25%2A%28+50+%2B+x+%29+\"$
\n" ); document.write( " $\"+7.5+%2B+x+=+12.5+%2B+.25x+\"$
\n" ); document.write( " $\"+.75x+=+12.5+-+7.5+\"$
\n" ); document.write( " $\"+.75x+=+5+\"$
\n" ); document.write( " $\"+x+=+6.667+\"$
\n" ); document.write( "6.667 ml of pure acid must be added
\n" ); document.write( "check:
\n" ); document.write( " $\"+%28+7.5+%2B+x+%29+%2F+%28+50+%2B+x+%29+=+.25+\"$
\n" ); document.write( " $\"+%28+7.5+%2B+6.667+%29+%2F+%28+50+%2B+6.667+%29+=+.25+\"$
\n" ); document.write( " $\"+14.1667+%2F+56.667+=+.25+\"$
\n" ); document.write( " $\"+14.1667+=+14.1667+\"$
\n" ); document.write( "OK \n" ); document.write( "

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