I love that. I had to do a similar calculation for how much change would be needed for a film festival. I was a volunteer that handled the cash and we needed to know how many $1, $5, $10 and $20 bills to have on hand so that we could always accept cash when people bought tickets.

I did a similar calculation making reasonable assumptions (most people buy two tickets at a time, most people pay with a $20 bill, etc.). It was fun and worked out quite accurately.

Best part was taking the actual funds collected and reevaluating to minimize the amount of cash needed.