Question 388199
 The revenue from selling x units of a product is given by y = -0.0002x2 + 20x. How many units must be sold in order to have the greatest revenue? (Find the x-coordinate of the vertex of the parabola.) 

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Max occurs when x = -b/2a
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x = -20/(2*-0.0002) = 50,000
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Cheers,
Stan H.