Hi Melissa,
You have a few typos in your post, so before I begin to answer the question, I have to state what I believe the question really is.
1) the fixed cost is $300,000 per year
2) the variable cost per person in attendance is $24
3) the revenue per person in attendance is $100.
So, we want to solve the following equation.
300000 + 24x = 100x
where x = # people in attendance
Solving for x
300000 = 76x
3047..37 = x
There must be 3,047.37 people in attendance to break even. But since you can't have partial people, the orchestra must sell 3,048 tickets.
Please note, my assumptions/understanding as noted in 1, 2 & 3, above may not be correct.