Lets assume that the amusement park is near a large city with a population of 8 million. If we assume that the average person lives to be 80 then we have 1 million people per age group. I would think that the older someone is the less likely they are to visit the amusement park in a given year. So lets say 80% of the people younger than 10 go and the number goes down for each 10 year period. We can add up the results for each 10 year period to get how many people we expect to have during a year. This estimation could be slightly high because not everyone in the city will be able to go to the park but I think that is compensated for by the fact that many people would travel to the park from outside of the city. Once you have that number you can look at the different revenue streams. I can think of three major revenue streams for amusement parks. Ticket sales, food, and souvenirs. We can multiply the total visitors by the ticket sales to get that number. We can then multiply the total visitors by a percentage of how many we think would buy food and multiply that product by the average amount we expect someone to spend on food. We can do similar calculation for the souvenir revenue.