document.write( "Question 857336: How much pure acid should be mixed with 5 gallons of a 40% acid solution in order to get a 90% acid solution \n" ); document.write( "

Algebra.Com's Answer #516528 by josmiceli(19441) $\"\"$ $\"About$

You can put this solution on YOUR website!
Let $\"+x+\"$ = gallons of pure acid to be added
\n" ); document.write( " $\"+.4%2A5+=+2+\"$ = gallons of pure acid in 40% solution
\n" ); document.write( "-----------------
\n" ); document.write( " $\"+%28+x+%2B+2+%29+%2F+%28+x+%2B+5+%29+=+.9+\"$
\n" ); document.write( " $\"+x+%2B+2+=+.9%2A%28+x+%2B+5+%29+\"$
\n" ); document.write( " $\"+x+%2B+2+=+.9x+%2B+4.5+\"$
\n" ); document.write( " $\"+.1x+=+2.5+\"$
\n" ); document.write( " $\"+x+=+25+\"$
\n" ); document.write( "25 gallons of pure acid must be added
\n" ); document.write( "check:
\n" ); document.write( " $\"+%28+x+%2B+2+%29+%2F+%28+x+%2B+5+%29+=+.9+\"$
\n" ); document.write( " $\"+%28+25+%2B+2+%29+%2F+%28+25+%2B+5+%29+=+.9+\"$
\n" ); document.write( " $\"+27+%2F+30+=+.9+\"$
\n" ); document.write( " $\"+9%2F10+=+.9+\"$
\n" ); document.write( "OK \n" ); document.write( "

\n" );