document.write( "Question 1104555: Dr. Jekyll needs 12 liters of a 40% solution to become Mr. Hyde.
\n" ); document.write( "He must mix a 20% solution and a 50% solution. How many liters of
\n" ); document.write( "each will be required to obtain what he needs?
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Algebra.Com's Answer #719270 by josmiceli(19441)\"\" \"About 
You can put this solution on YOUR website!
Let \"+a+\" = liters of 20% solution needed
\n" ); document.write( "Let \"+b+\" = liters of 50% solution needed
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\n" ); document.write( "(1) \"+a+%2B+b+=+12+\"
\n" ); document.write( "(2) \"+%28+.2a+%2B+.5b+%29+%2F+12+=+.4+\"
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\n" ); document.write( "(2) \"+.2a+%2B+.5b+=+4.8+\"
\n" ); document.write( "(2) \"+2a+%2B+5b+=+48+\"
\n" ); document.write( "Multiply both sides of (1) by \"+2+\"
\n" ); document.write( "and subtract (1) from (2)
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\n" ); document.write( "(2) \"+2a+%2B+5b+=+48+\"
\n" ); document.write( "(1) \"+-2a+-+2b+=+-24+\"
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\n" ); document.write( "\"+3b+=+24+\"
\n" ); document.write( "\"+b+=+8+\"
\n" ); document.write( "and
\n" ); document.write( "(1) \"+a+%2B+8+=+12+\"
\n" ); document.write( "(1) \"+a+=+4+\"
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\n" ); document.write( "4 liters of 20% solution are needed
\n" ); document.write( "8 liters of 50% solution are needed
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\n" ); document.write( "check:
\n" ); document.write( "(2) \"+%28+.2a+%2B+.5b+%29+%2F+12+=+.4+\"
\n" ); document.write( "(2) \"+%28+.2%2A4+%2B+.5%2A8+%29+%2F+12+=+.4+\"
\n" ); document.write( "(2) \"+%28+.8+%2B+4+%29+%2F+12+=+.4+\"
\n" ); document.write( "(2) \"+4.8+=+.4%2A12+\"
\n" ); document.write( "(2) \"+4.8+=+4.8+\"
\n" ); document.write( "OK\r
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