document.write( "Question 436332: Soybean is 18% protein
\n" ); document.write( "Cornmeal is 9% protein
\n" ); document.write( "How many lbs of each should be mixed together to get 360-lb mixture that is 12% protein? \n" ); document.write( "

Algebra.Com's Answer #301872 by josmiceli(19441) $\"\"$ $\"About$

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Let $\"a\"$ = pounds of soybean needed
\n" ); document.write( "Let $\"b\"$ = pounds of cornmeal needed
\n" ); document.write( "given:
\n" ); document.write( " $\"+.18a+\"$ = protein in soybeans
\n" ); document.write( " $\"+.09b+\"$ = protein in cornmeal
\n" ); document.write( "(1) $\"+a+%2B+b+=+360+\"$
\n" ); document.write( "(2) $\"%28++.18a+%2B+.09b+%29%2F360+=+.12+\"$
\n" ); document.write( "-----------------------
\n" ); document.write( "(2) $\"%28++.18a+%2B+.09b+%29%2F360+=+.12+\"$
\n" ); document.write( "(2) $\"++.18a+%2B+.09b++=+.12%2A360+\"$
\n" ); document.write( "(2) $\"++.18a+%2B+.09b++=+43.2+\"$
\n" ); document.write( "(2) $\"++18a+%2B+9b++=+4320+\"$
\n" ); document.write( "Multiply both sides of (1) by $\"9\"$ and
\n" ); document.write( "subtract (1) from (2)
\n" ); document.write( "(2) $\"++18a+%2B+9b++=+4320+\"$
\n" ); document.write( "(1) $\"+-9a+-+9b+=+-3240+\"$
\n" ); document.write( " $\"+9a+=+1080+\"$
\n" ); document.write( " $\"+a+=+120+\"$
\n" ); document.write( "and
\n" ); document.write( "(1) $\"+120+%2B+b+=+360+\"$
\n" ); document.write( " $\"+b+=+240+\"$
\n" ); document.write( "120 pounds of soybeans are needed
\n" ); document.write( "240 pounds of cornmeal are needed
\n" ); document.write( "check answer:
\n" ); document.write( "(2) $\"%28++.18%2A120+%2B+.09%2A240+%29%2F360+=+.12+\"$
\n" ); document.write( "(2) $\"%28++21.6+%2B+21.6+%29%2F360+=+.12+\"$
\n" ); document.write( "(2) $\"+43.2%2F360+=+.12+\"$
\n" ); document.write( " $\"+43.2+=+.12%2A360+\"$
\n" ); document.write( " $\"+43.2+=+43.2+\"$
\n" ); document.write( "OK \n" ); document.write( "

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