document.write( "Question 87971: a coffee merchant has coffee beans that sell for $9 per pund and &12 per pound. The two types are to be mixed to create 100LB of mixture that will sell for $11.25 per pound. How much of each type of bean should be used in the mixture? \n" ); document.write( "
Algebra.Com's Answer #63867 by tutorcecilia(2152)\"\" \"About 
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Let x = beans @ $9
\n" ); document.write( "Let y = beans @ $12
\n" ); document.write( "Total cost = (100)(11.25) = $1,125
\n" ); document.write( ".
\n" ); document.write( "So, x+y= 100lbs
\n" ); document.write( "y=100-x
\n" ); document.write( ".
\n" ); document.write( "$9(x)+$12(y)=$1,125
\n" ); document.write( "9x+12(100-x)=1125 [substitute (y=100-x)]
\n" ); document.write( "9x+1200-12x=1125 [simplify and combine like-terms]
\n" ); document.write( "-3x+1200=1125 [solve for the x-term]
\n" ); document.write( "-3x+1200-1200=1125-1200
\n" ); document.write( "-3x=-75
\n" ); document.write( "-3x/-3x=-75/3
\n" ); document.write( "x=25 lbs at $9.00/lb
\n" ); document.write( ".
\n" ); document.write( "So, plugging in (x=25), solve for the y-term:
\n" ); document.write( "x+y=100
\n" ); document.write( "25+y=100
\n" ); document.write( "y=100-25
\n" ); document.write( "y=75 at $12.00/lb
\n" ); document.write( ".
\n" ); document.write( "Plug-in the x and y values:\r
\n" ); document.write( "\n" ); document.write( "$9(x)+$12(y)=$1,125
\n" ); document.write( "9(25)+12(75)=1,125
\n" ); document.write( "1125=1125 [checks out]\r
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