document.write( "Question 631697: How many gallons of pure alcohol must be mixed with 5 gallons of a solution that is 20 percent to make a solution that is 50% alcohol? \n" ); document.write( "

Algebra.Com's Answer #397770 by josmiceli(19441) $\"\"$ $\"About$

You can put this solution on YOUR website!
Let $\"+a+\"$ = gallons of pure alcohol needed
\n" ); document.write( " $\"+.2%2A5+=+1+\"$ gallons of pure alcohol in 20% solution
\n" ); document.write( "given:
\n" ); document.write( " $\"+%28+a+%2B+1+%29+%2F+%28+a+%2B+5+%29+=+.5+\"$
\n" ); document.write( " $\"+a+%2B+1+=+.5%2A%28+a+%2B+5+%29+\"$
\n" ); document.write( " $\"+a+%2B+1+=+.5a+%2B+2.5+\"$
\n" ); document.write( " $\"+a+-+.5a+=+2.5+-+1+\"$
\n" ); document.write( " $\"+.5a+=+1.5+\"$
\n" ); document.write( " $\"+a+=+3+\"$
\n" ); document.write( "3 gallons of pure alcohol are needed
\n" ); document.write( "check:
\n" ); document.write( " $\"+%28+a+%2B+1+%29+%2F+%28+a+%2B+5+%29+=+.5+\"$
\n" ); document.write( " $\"+%28+3+%2B+1+%29+%2F+%28+3+%2B+5+%29+=+.5+\"$
\n" ); document.write( " $\"+4%2F8+=+.5+\"$
\n" ); document.write( " $\"+.5+=+.5+\"$
\n" ); document.write( "OK \n" ); document.write( "

\n" );