A Manufacturer Finds That the Revenue Generated by Selling X $R ( x ) = 40 x - 0.2 x ^ { 2 }$

Essay

A manufacturer finds that the revenue generated by selling x units of a certain commodity is given by the function, $R ( x ) = 40 x - 0.2 x ^ { 2 }$
where the revenue $R ( x )$
is measured in dollars. What is the maximum revenue, and how many units should be manufactured to obtain this maximum?