document.write( "Question 1108141: Gabe Amodeo, a nuclear physicist, needs 30 liters of a 40% acid solution. He currently has a 30% solution and a 60% solution. How many liters of each does he need to make the needed 30 liters of 40% acid solution? \n" ); document.write( "

Algebra.Com's Answer #723149 by josmiceli(19441) $\"\"$ $\"About$

You can put this solution on YOUR website!
Let $\"+a+\"$ = liters of 30% sloution needed
\n" ); document.write( "Let $\"+b+\"$ = liters of 60% solution needed
\n" ); document.write( "----------------------------------------
\n" ); document.write( "(1) $\"+a+%2B+b+=+30+\"$
\n" ); document.write( "(2) $\"+%28+.3a+%2B+.6b+%29+%2F+30+=+.4+\"$
\n" ); document.write( "---------------------------------
\n" ); document.write( "(2) $\"+.3a+%2B+.6b+=+12+\"$
\n" ); document.write( "(2) $\"+3a+%2B+6b+=+120+\"$
\n" ); document.write( "(2) $\"+a+%2B+2b+=+40+\"$
\n" ); document.write( "Subtract (1) from (2)
\n" ); document.write( "(2) $\"+a+%2B+2b+=+40+\"$
\n" ); document.write( "(1) $\"+-a+-+b+=+-30+\"$
\n" ); document.write( "---------------------
\n" ); document.write( " $\"+b+=+10+\"$
\n" ); document.write( "and
\n" ); document.write( "(1) $\"+a+%2B+10+=+30+\"$
\n" ); document.write( "(1) $\"+a+=+20+\"$
\n" ); document.write( "He needs 20 liters of 30% solution
\n" ); document.write( "and 10 liters of 60% solution
\n" ); document.write( "----------------------------------
\n" ); document.write( "check:
\n" ); document.write( "(2) $\"+%28+.3a+%2B+.6b+%29+%2F+30+=+.4+\"$
\n" ); document.write( "(2) $\"+%28+.3%2A20+%2B+.6%2A10+%29+%2F+30+=+.4+\"$
\n" ); document.write( "(2) $\"+%28+6+%2B+6+%29+%2F+30+=+.4+\"$
\n" ); document.write( "(2) $\"+12+=+.4%2A30+\"$
\n" ); document.write( "(2) $\"+12+=+12+\"$
\n" ); document.write( "OK \n" ); document.write( "

\n" );