Answer:
Ticket price 11,5 $  
R(max)  =  132750 $
Step-by-step explanation:INCOMPLETE QUESTION
The ticket price is missing 
We will assume 12 $
Let call x the decreasing number of the ticket price
The revenue is
R =  ticket price * numbers of spectator
R(x) =  (  12 - x ) *  ( 11000 + 1000*x )   for all   0 ≤ x  ≤ 4   ( the seating capacity is 15000 )
R(x) =  132000 + 12000*x  - 11000*x - 1000*x²
R(x) =  132000 + 1000*x  - 1000*x²
Taking derivatives on both sides of the equatio we get:
R´(x)  =  1000  -  2000x
R´(x)  = 0    ⇒    1000  -  2000x  =  0
x  =  1000/2000    ⇒  x = 0,5 $
We notice that R´´(x)  < 0    then we have a maximum for  x = 0,5
and the price is 12 - 0,5  = 11,5 $ for ticket
and the R(max) is
R(max) = 132000 + 1000*0,5  + 1000* (0,5)²
R(max) = 132000 + 500 + 250
R(max) = 132750 $