document.write( "Question 1184212: Diana runs a factory that makes DVD players. Each R80 takes 6 ounces of plastic and 2 ounces of metal. Each FS20 requires 2 ounces of plastic and 4 ounces of metal. The factory has 140 ounces of plastic, 200 ounces of metal available, with a maximum of 12 R80 that can be built each week. If each R80 generates $5 in profit, and each FS20 generates $7, how many of each of the DVD players should Diana have the factory make each week to make the most profit?\r
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Algebra.Com's Answer #815204 by Theo(13342)\"\" \"About 
You can put this solution on YOUR website!
make a table such as the one below:\r
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document.write( "product name           R80           FS20\r\n" );
document.write( "number of units         x              y        x >= 0, y >= 0, x <= 12\r\n" );
document.write( "plastic                 6              2        6x + 2y <= 140\r\n" );
document.write( "metal                   2              4        2x + 4y <= 200\r\n" );
document.write( "profit                  5              7        maximize 5x + 7y\r\n" );
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\n" ); document.write( "\n" ); document.write( "objective function is profit = 5x + 7y
\n" ); document.write( "this is what you want to maximize.\r
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\n" ); document.write( "\n" ); document.write( "constraint functions:
\n" ); document.write( "x >= 0
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\n" ); document.write( "6x + 2y <= 140
\n" ); document.write( "2x + 4y <= 200\r
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\n" ); document.write( "\n" ); document.write( "using the desmos.com calculator, you graph the opposite of the constraint functions and evaluate each corner point of the feasible region with the objective function.\r
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\n" ); document.write( "\n" ); document.write( "the feasible region is the area of the graph that is not shaded.\r
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\n" ); document.write( "\n" ); document.write( "here's the graph.\r
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\n" ); document.write( "\n" ); document.write( "the corner points of the feasible region and the value of the objective function at those corner points are:\r
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\n" ); document.write( "\n" ); document.write( "(0,50) = 5x + 7y becomes 5*0 + 7*50 = 350
\n" ); document.write( "(8,46) = 5x + 7y becomes 5*8 + 46*7 = 362 ***** maximum profit is here.
\n" ); document.write( "(12,34) = 5x + 7y becomes 5*12 + 7*34 = 298
\n" ); document.write( "(12,0) = 5x + 7y becomes 5*12 + 7*0 = 60\r
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\n" ); document.write( "\n" ); document.write( "the maximum profit is at (8,46), where it is equal to 362.
\n" ); document.write( "(8,46) means the value of x is 8 and the value of y is 46.\r
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\n" ); document.write( "\n" ); document.write( "the constraint functions must all be true at this point.\r
\n" ); document.write( "\n" ); document.write( "x <= 12 is true.
\n" ); document.write( "x >= 0, y >= 0 is true.
\n" ); document.write( "6x + 2y becomes 6*8 + 2*46 = 140 which is <= 140, so this is true.
\n" ); document.write( "2x + 4y becomes 2*8 + 4*46 = 200 which is <= 200, so this is true.\r
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\n" ); document.write( "\n" ); document.write( "all constraints are true at the maximum profit point of (8,46).
\n" ); document.write( "this confirms the solution at (8,46) is valid.\r
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