Given: The entrance fee in contest = $20 and
Winner prize amount = $500.
Also what is left over after paying the winner the function :
f(x) = 20x-500, describes how much money Micah earns if x people enter the contest.
Solution: Let us find inverse function first.
Writing given function in terms of y.
y = 20x-500
Switching x and y, we get
x = 20y -500.
Now, solving it for y, we get
x +500 = 20y

.
Therefore, inverse function describes that the total number of people entered in the contest is the sum of winning amount and Micah's earning amount over the entrance fee of each contestant.