5. Miss Andrea’s Dance Studio is considering offering an additional ballet class for adult students 21 years of age or older. The market rate is $10 per student per class. Miss Andrea can teach the class herself or pay another teacher $20 per class. She doesn’t think her utility or insurance costs will change as a result of offering this class. No other costs matter. If she doesn’t offer the ballet class, Miss Andrea can rent her studio space to a ballroom dancing instructor who will pay her $30 per hour for using the space.