From the given, the revenue is given to be equal to,
r(p) = -2.5p^2 + 850p
To determine the price at which the maximum revenue is realized, we derive the equation and equate to zero as shown below.
dr(p) = -5p + 850
Equating to zero,
0 = -5p + 850
The value of p from the equation is 170.
Answer: $170