Answer
Maximum revenue when $p={\$} 140$
$R={\$} 9800.$
Work Step by Step
$q=-0.5p+140$period
Revenue$:$$R=pq$
$ R(p)=-0.5p^{2}+140p$.
has a parabola (that opens down) for a graph.
$a=-0.5, b=140, c=0.$
Maximum revenue occurs at the vertex, when
$p=-\displaystyle \frac{b}{2a}=-\frac{140}{2(-0.5)}={\$} 140$
The corresponding revenue is
$R=-0.5(140)^{2}+140(140)={\$} 9800.$
Maximum revenue when $p={\$} 140$
$R={\$} 9800.$
