The local chapter of the Rotary Foundation is planning a fundraiser. They estimate that renting the auditorium and paying for the sound system and performers and other costs would come to $15,000. They expect to charge $50 per person. Variable costs are negligible.

Required:
a. What is the required attendance for the chapter to raise $21,000 toward charity?
b. The chapter also proposes to have a cash bar at the event. They estimate that the average patron would spend $20 and that the contribution margin ratio would be 50%. How does this data change your answer to part (a)?