document.write( "Question 227475: How many liters of 20% solution and how many liters of 70% solution must be combineed to produce five liters of 40% solution? \n" ); document.write( "

Algebra.Com's Answer #169020 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 70% solution needed
\n" ); document.write( " $\"%28.2a+%2B+.7b%29%2F5+=+.4\"$
\n" ); document.write( " $\".2a+%2B+.7b+=+2\"$
\n" ); document.write( "(1) $\"2a+%2B+7b+=+20\"$
\n" ); document.write( "(2) $\"a+%2B+b+=+5\"$
\n" ); document.write( "Multiply both sides of (2) by $\"2\"$
\n" ); document.write( "and subtract from (1)
\n" ); document.write( "(1) $\"2a+%2B+7b+=+20\"$
\n" ); document.write( "(2) $\"-2a+%2B+-2b+=+-10\"$
\n" ); document.write( " $\"5b+=+10\"$
\n" ); document.write( " $\"b+=+2\"$
\n" ); document.write( "and, since
\n" ); document.write( " $\"a+%2B+b+=+5\"$
\n" ); document.write( " $\"a+=+5+-+b\"$
\n" ); document.write( " $\"a+=+5+-+2\"$
\n" ); document.write( " $\"a+=+3\"$
\n" ); document.write( "2 liters of 20% solution and 3 liters of 70%
\n" ); document.write( "solution are needed\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "

\n" );