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Solve using the quadratic formula

  1. Mar 29, 2006 #1


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    A large dealership had been selling new cars at $6000 over the factory price. Sales have been averaging 80 cars per mouth. Because of inflation, the $6000 markup is going to be increased. The marketing manager has determined that, for every $100 increase, there will be one less car
    sold each month. What should the new markup be in order to maximize the revenue?

    Let x rep the number of $100 increases
    the equation for revenu is (#sold)(price)
    so (80-x)(6000+100x)
    then, when you expand it its -100x^2+2000x+480 000
    next, solve using the quadratic formula
    is everything right?

  2. jcsd
  3. Mar 29, 2006 #2


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    Why would you find the values of x giving zero profit?

    Find the MAXIMUM of the given profit function, not its roots.
  4. Mar 29, 2006 #3


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    ^ok, thanks, so if my work abouve was correct, the answer should be a maximum of 490 000, when x=10
    Last edited: Mar 29, 2006
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