document.write( "Question 1203126: At a price of $70 for a blender, Home Outfitters will sell 12 in one month. Market research has shown that for every $5 decrease in the price of a blender, they will be able to sell 3 more each month.\r
\n" ); document.write( "\n" ); document.write( "a) Determine the price of a blender that will maximize revenue for the month.\r
\n" ); document.write( "\n" ); document.write( "b) Approximately how many blenders will be sold to reach revenue of $1100?
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Algebra.Com's Answer #838443 by Theo(13342)\"\" \"About 
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revenue = price * quantity sold
\n" ); document.write( "when price = 70, quantity = 12 making revenue = 70 * 12 = 840.
\n" ); document.write( "when the price decreases by 5 dollars, the quantity sold increased by 3 dollars.
\n" ); document.write( "let x equal the number of times the price decreases and the quantity increases.
\n" ); document.write( "the equation becomes revenue = (70 - 5x) * (12 + 3x)
\n" ); document.write( "when x = 0, revenue = 70 * 12 = 840
\n" ); document.write( "when x = 1, revenue = 65 * 15 = 975
\n" ); document.write( "when x = 2, revenue = 60 * 18 = 1080
\n" ); document.write( "when x = 3, revenue = 55 * 21 = 1155\r
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\n" ); document.write( "\n" ); document.write( "your revenue equation is y = (70 - 5x) * (12 + 3x).
\n" ); document.write( "simpiify to get y = 840 + 150x - 15x^2.
\n" ); document.write( "rearrange by descending order of degree to get -15x^2 + 150x + 840.\r
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\n" ); document.write( "\n" ); document.write( "for the revenue to be equal to 1100, the equaton becomes:
\n" ); document.write( "-15x^2 + 150x + 840 = 1100
\n" ); document.write( "subtract 1100 from both sides of the equation to get -15x^2 + 150x + 840 -1100 = 0.
\n" ); document.write( "combine like terms to get -15x^2 + 150x - 260 = 0.
\n" ); document.write( "multiply both sides of the equation by -1 to get 15x^2 - 150x + 260 = 0.
\n" ); document.write( "factor the equation to get x = 7.7688746209727 or x = 2.2311253790273.\r
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\n" ); document.write( "\n" ); document.write( "your original equation is y = -15x^2 + 150x + 840
\n" ); document.write( "the general form of this equation is y = ax^2 + bx + c.
\n" ); document.write( "y will be maximum when x = -b/(2a) = -150/-30 = 5.
\n" ); document.write( "when x = 5, y = -15*5^2 + 150*5 + 840 = 1215.
\n" ); document.write( "that's the maximum revenue.
\n" ); document.write( "it occurs when the price is 70 - 5*5 = 45 and the number of blenders sold is 12 + 5*3 = 27.
\n" ); document.write( "45 * 27 = max revenue of 1215.
\n" ); document.write( "this is shown on the graph at the point (5,1215).
\n" ); document.write( "the value of x is 5 for the maximum revenue.
\n" ); document.write( "this means 5 increments of 5 dollars less for the price and 5 increments of 3 units more for the quantity.\r
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\n" ); document.write( "\n" ); document.write( "the number of increments is not an integer when you want the revenue to be exactly 1100.
\n" ); document.write( "the values of x that allow a revenue of at or above 1100 are 2.2311253790273 <= x <= 7.7688746209727.
\n" ); document.write( "if you want to make the increments integer, then you would choose x = 3 to 7.
\n" ); document.write( "that would make the revenue greater than 1100.\r
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\n" ); document.write( "\n" ); document.write( "here are two displays of the graph and one display of the spreadshee i used to make the calculations.\r
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\n" ); document.write( "\n" ); document.write( "i'll be available to answer any questions you might have.
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