document.write( "Question 960240: A shoe store sells a new model of athletic shoe for $90. On average, the store sells 45 pairs of these shoes each week. Jason, the sales manager, estimates that he will sell 4 additional pairs of shoes each week for every $5 reduction in the price.\r
\n" ); document.write( "\n" ); document.write( "Find the following:
\n" ); document.write( "1.) A quadratic function modeling the store's average weekly revenue from the sales of these shoes as related to reduction in price.
\n" ); document.write( "2.) The range of prices which would allow the store to maintain or increase its current weekly revenue from these shoes.
\n" ); document.write( "3.) The maximum amount by which the store can increase its revenue from these shoes each week. Round off to the nearest whole dollar.
\n" ); document.write( "

Algebra.Com's Answer #586832 by josmiceli(19441)\"\" \"About 
You can put this solution on YOUR website!
Let \"+R+\" = average weekly revenue
\n" ); document.write( "Let \"+n+\" = number of $5 reductions in the price of shoes
\n" ); document.write( "--------------------------
\n" ); document.write( "(1)
\n" ); document.write( "\"+R+=+%28+45+%2B+4n+%29%2A%28+90+-+5n+%29+\"
\n" ); document.write( "\"+R+=+4050+%2B+360n+-+225n+-+20n%5E2+\"
\n" ); document.write( "\"+R+=+-20n%5E2+%2B+135n+%2B+4050+\"
\n" ); document.write( "-------------------------------
\n" ); document.write( "(2)
\n" ); document.write( "Current weekly revenue is \"+45%2A90+=+4050+\"
\n" ); document.write( "I need values for \"+n+\" for which \"+R+%3E=+4050+\"
\n" ); document.write( "\"+4050+=+-20n%5E2+%2B+135n+%2B+4050+\"
\n" ); document.write( "\"+0+=+-20n%5E2+%2B+135n+\"
\n" ); document.write( "\"+0+=+5n%2A%28+-4n+%2B+27+%29+\"
\n" ); document.write( "The solutions are:
\n" ); document.write( "\"+n+=+0+\"
\n" ); document.write( "\"+-4n+%2B+27+=+0+\"
\n" ); document.write( "\"+4n+=+27+\"
\n" ); document.write( "\"+n+=+6.75+\"
\n" ); document.write( "------------------
\n" ); document.write( "The price per shoe when \"+n+=+6.75+\" is
\n" ); document.write( "\"+90+-+5n+=+90+-+5%2A6.75+\"
\n" ); document.write( "\"+90+-+5n+=+90+-+33.75+\"
\n" ); document.write( "\"+90+-+5n+=+56.25+\"
\n" ); document.write( "----------------------
\n" ); document.write( "The range of prices to maintain or increase is
\n" ); document.write( "$56.25 to $90
\n" ); document.write( "---------------
\n" ); document.write( "check:
\n" ); document.write( "\"+R+=+%28+45+%2B+4%2A6.75+%29%2A%28+90+-+5%2A6.75+%29+\"
\n" ); document.write( "\"+R+=+%28+45+%2B+27+%29%2A56.25+\"
\n" ); document.write( "\"+R+=+72%2A56.25+\"
\n" ); document.write( "\"+R+=+4050+\"
\n" ); document.write( "----------------------
\n" ); document.write( "(3)
\n" ); document.write( "I want the maximum possible \"+R+\"
\n" ); document.write( "This is where \"+n%5Bmax%5D+=+-b%2F%282a%29+\"
\n" ); document.write( "\"+a+=+-20+\"
\n" ); document.write( "\"+b+=+135+\"
\n" ); document.write( "\"+n%5Bmax%5D+=+-135+%2F+%28+2%2A%28-20%29%29+\"
\n" ); document.write( "\"+n%5Bmax%5D+=+3.375+\"
\n" ); document.write( "Plug this back in and find \"+R%5Bmax%5D+\"
\n" ); document.write( "----------------------------------
\n" ); document.write( "\"+R%5Bmax%5D+=+%28+45+%2B+4%2A3.375+%29%2A%28+90+-+5%2A3.375+%29+\"
\n" ); document.write( "\"+R%5Bmax%5D+=+%28+45+%2B+13.5+%29%2A%28+90+-+16.875+%29+\"
\n" ); document.write( "\"+R%5Bmax%5D+=+58.5%2A73.125+\"
\n" ); document.write( "\"+R%5Bmax%5D+=+4277.81+\"
\n" ); document.write( "The maximum amount by which the store can
\n" ); document.write( "increase its revenue from these shoes each week is
\n" ); document.write( "$4,277.81
\n" ); document.write( "---------------------
\n" ); document.write( "Here's the plot of the \"+R+\" function:
\n" ); document.write( "\"+graph%28+500%2C+500%2C+-4%2C+20%2C+-200%2C+4700%2C+-20x%5E2+%2B+135x+%2B+4050+%29+\"\r
\n" ); document.write( "\n" ); document.write( " \r
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\n" ); document.write( "\n" ); document.write( "
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