It takes a phlebotomist 10 minutes to finish a blood draw. The supplies for each draw cost $5, and the phlebotomist earns $25 per hour.

It takes a phlebotomist 10 minutes to finish a blood draw. The supplies for each draw cost $5, and the phlebotomist earns $25 per hour. The phlebotomy lab is designed to accommodate 24,000 draws per year. Its rent is $100,000 per year. What are the average and marginal costs of a blood draw when the volume is 24,000? 12,000? Explain your results.