document.write( "Question 503890: How many gallons of a 25% alcohol solution must be mixed with 20 gallons of a 50% alcohol solution to make 30 gallons of a 40% alcohol solution? \n" ); document.write( "

Algebra.Com's Answer #339446 by josmiceli(19441) $\"\"$ $\"About$

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Let $\"a\"$ = gallons of 25% solution needed
\n" ); document.write( "given:
\n" ); document.write( " $\"+.25a+\"$ = gallons of alcohol in 25% solution
\n" ); document.write( " $\"+.5%2A20+=+10+\"$ gallons of alcohol in 50% solution
\n" ); document.write( "--------------
\n" ); document.write( " $\"+%28+.25a+%2B+10+%29+%2F+30+=+.4+\"$
\n" ); document.write( " $\"+.25a+%2B+10+=+.4%2A30+\"$
\n" ); document.write( " $\"+.25a+=+12+-+10+\"$
\n" ); document.write( " $\"+.25a+=+2+\"$
\n" ); document.write( " $\"+a+=+8+\"$
\n" ); document.write( "8 gallons of 25% solution is needed
\n" ); document.write( "check:
\n" ); document.write( " $\"+%28+.25a+%2B+10+%29+%2F+30+=+.4+\"$
\n" ); document.write( " $\"+%28+.25%2A8+%2B+10+%29+%2F+30+=+.4+\"$
\n" ); document.write( " $\"+12%2F30+=+.4+%7D%7D%0D%0A%7B%7B%7B+12+=+12+\"$
\n" ); document.write( "OK \n" ); document.write( "

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