Sunrise Coffee has determined that the cost, in dollars, of harvesting $x$ acres of coffee beans is given

by $C(x)=5300+2\mathrm{.}3x^{0\mathrm{.}4}$ and that the revenue from the sale of beans from $x$ acres is given by

$R(x)=58x^{0\mathrm{.}8}.$

$($c$)$ Find the rate at which the profit is changing when $55$ acres of beans have been harvested and

sold. Round to the nearest hundredth and report your answer with appropriate units.

$($d$)$ Find the average profit of harvesting and seiling beans from $x$ acres. Simplify your answer,

$($e$)$ Find the rate at which average profit is changing when $55$ acres of beans have been harvested

and sold. Round to the nearest hundredth and report your answer with appropriate units.