Problem:
A garage band wants to hold a concert. The expected crowd is 3,000. The average expenditure on concessions is $15. Tickets sell for $10 each, and the band's profit is 80% of the gate, along with concession sales, minus a fixed cost of $10,000.
Question: Develop a general mathematical model and implement it on a spreadsheet to find their expected profit. Please provide step by step solution and show all work.