document.write( "Question 235962: Pedro is making brown paint by mixing 4 parts green paint with 5 parts red paint. He wants to make 36 gallons of brown paint. How many gallons of red paint will Pedro need? \n" ); document.write( "

Algebra.Com's Answer #173733 by josmiceli(19441) $\"\"$ $\"About$

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Let $\"r\"$ = gallons of red paint needed
\n" ); document.write( "Let $\"g\"$ = gallons of green paint needed
\n" ); document.write( "given:
\n" ); document.write( "(1) $\"r+%2B+g+=+36\"$
\n" ); document.write( "(2) $\"r%2Fg+=+4%2F5\"$
\n" ); document.write( "----------------
\n" ); document.write( "From (2)
\n" ); document.write( "(2) $\"5r+=+4g\"$
\n" ); document.write( "(2) $\"5r+-+4g+=+0\"$
\n" ); document.write( "Multiply both sides of (1) by $\"4\"$
\n" ); document.write( "and add (2) to (1)
\n" ); document.write( "(1) $\"4r+%2B+4g+=+144\"$
\n" ); document.write( "(2) $\"5r+-+4g+=+0\"$
\n" ); document.write( " $\"9r+=+144\"$
\n" ); document.write( " $\"r+=+16\"$
\n" ); document.write( "and, since
\n" ); document.write( "(1) $\"r+%2B+g+=+36\"$
\n" ); document.write( " $\"16+%2B+g+=+36\"$
\n" ); document.write( " $\"g+=+20\"$
\n" ); document.write( "16 gallons of red and 20 gallons of green are needed\r
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