What is the selling price per widget as a function of the number of widgets produced, and what should the
selling price be if 15 widgets are produced?

1240 widgets

Step-by-step explanation:

The value of the function at 870, the local maximum, is

= -0.02(870)2 + 34.80(870) - 4700

= -0.02(756900) + 30276 - 4700

=  -15138 + 25576

= 10438

So the vertex is (870, 10438)

The cost t the company to produce 870 widgets is  

C(870) = 4700 + 5.20(870) = 4700 + 4524 = 9224

So, the cost of the widgets plus the profit must be equal to the total sales, which is divided by the number of widgets reveal their individual price.

(10438 + 9224)/870 = 19662/870 = $22.60

P(x) = 7700

- 0.02x2 + 34.80x - 4700 = 7700

-0.02x2 + 34.80x -12400 = 0

x = {-34.80 ± √[(34.80)2 - 4(-0.02)(-12400)]}/2(-0.02)

x = [-34.80 ± √(1211.04 - 992)]/(-0.04)

x = (-34.80 ± √219.04)/(-0.04)

x = (-34.80 ± 14.8)/(-0.04)

x = 870 ± 370

so, $7700 in profits will be earned at either 500 widgets or 1240 widgets

its a straight line parallel to the time axis