document.write( "Question 990144: an electronic store sells an average of 52 laptops per month at an average selling price that is $600 more than the cost price. for every $40 increase in the selling price, the store sells two fewer laptops. What amount over the cost price will maximize the revenue? \n" ); document.write( "

Algebra.Com's Answer #610260 by ankor@dixie-net.com(22740) $\"\"$ $\"About$

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an electronic store sells an average of 52 laptops per month at an average selling price that is $600 more than the cost price.
\n" ); document.write( " for every $40 increase in the selling price, the store sells two fewer laptops.
\n" ); document.write( " What amount over the cost price will maximize the revenue?
\n" ); document.write( ":
\n" ); document.write( "let x = no. of 2 laptop decreases and also the no. of $40 increases
\n" ); document.write( "f(x) = (600 + 40x)(52 - 2x)
\n" ); document.write( "FOIL
\n" ); document.write( "f(x) = 31200 - 1200x + 2080x - 80x^2
\n" ); document.write( "f(x) = -80x^2 + 880x + 31200
\n" ); document.write( "Max occurs at the axis of symmetry; x = -b/(2a)
\n" ); document.write( "x = $\"%28-880%29%2F%282%2A-80%29\"$
\n" ); document.write( "x = 5.5
\n" ); document.write( "Find the amt over cost price
\n" ); document.write( "5.5(40) + 600 = $820 over cost at max revenue (selling 41 laptops) \n" ); document.write( "

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