document.write( "Question 1144648: How much of a 40% solution of alcohol and how much of a 80% solution should be mixed to give 40 gallons of a 50% solutions? \n" ); document.write( "

Algebra.Com's Answer #765813 by josmiceli(19441) $\"\"$ $\"About$

You can put this solution on YOUR website!
Let $\"+a+\"$ = gallons of 40% solution needed
\n" ); document.write( "Let $\"+b+\"$ = gallons of 80% solution needed
\n" ); document.write( "---------------------------------------------------
\n" ); document.write( "(1) $\"+%28+.4a+%2B+.8b+%29+%2F+40+=+.5+\"$
\n" ); document.write( "(2) $\"+a+%2B+b+=+40+\"$
\n" ); document.write( "------------------------------------
\n" ); document.write( "(1) $\"+.4a+%2B+.8b+=+20+\"$
\n" ); document.write( "(1) $\"+4a+%2B+8b+=+200+\"$
\n" ); document.write( "(1) $\"+a+%2B+2b+=+50+\"$ subtract (2) from (1)
\n" ); document.write( "(2) $\"+-a+-+b+=+40+\"$
\n" ); document.write( "---------------------------
\n" ); document.write( " $\"+b+=+10+\"$
\n" ); document.write( "and
\n" ); document.write( "(2) $\"+a+%2B+10+=+40+\"$
\n" ); document.write( "(2) $\"+a+=+30+\"$
\n" ); document.write( "---------------------------
\n" ); document.write( "30 gallons of 40% solution and 10 gallons of
\n" ); document.write( "80% solution are needed
\n" ); document.write( "----------------------------
\n" ); document.write( "check:
\n" ); document.write( "(1) $\"+%28+.4a+%2B+.8b+%29+%2F+40+=+.5+\"$
\n" ); document.write( "(1) $\"+%28+.4%2A30+%2B+.8%2A10+%29+%2F+40+=+.5+\"$
\n" ); document.write( "(1) $\"+%28+12+%2B+8+%29+%2F+40+=+.5+\"$
\n" ); document.write( "(1) $\"+20%2F40+=+.5+\"$
\n" ); document.write( "(1) $\"+20+=+20+\"$
\n" ); document.write( "OK\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "

\n" );