Answer
(a) $A=120-(\frac{P-200}{3})$
(b) 215
Work Step by Step
Let $A$ be total amount of tickets sold.
(a)
$A=120-(\frac{P-200}{3})$
(b)
To find the corresponding ticket price range, we have to find the ticket prices at key points $90$ and $115$.
$90=120-\frac{P-200}{3}$
$\frac{P-200}{3}=30$
$P-200=90$
$P=290$
$115=120-\frac{P-200}{3}$
$\frac{P-200}{3}=5$
$P-200=15$
$P=215$
