An accessories company finds that the cost and revenue, in dollars, of producing x belts is given by C(x) = 720 + 30x - 0.066x^2 and R(x) = 55x^(9/10), respectively. Determine the rate at which the accessories company's average profit per belt is changing when 179 belts have been produced and sold.
First, find the rate at which the average profit is changing when x belts have been produced.
P'(x) =
When 179 belts have been produced and sold, the average profit is changing at for each additional belt.
(Round to four decimal places as needed.)