Answer:
The answert is "$0.007 / bottle".
Step-by-step explanation:
Please find the complete question in the attachment file.
[tex]\to R(x) =7.5x^{0.7}[/tex]
The average income:
[tex]\to A(x) = \frac{R(x)}{x} =7.5 x^{-0.3}[/tex]
The change rate on the average revenue:
[tex]\to A'(x) =7.5(-0.3)x^{-1.3}[/tex]
when 81 bottles were produced , then the rate of change in average revenue
[tex]\to =A'(81)\\\\\to -0.007 \ / \ bottle[/tex]
The average income is decreasing at rate = $0.007 / bottle
