A new computer lets a phlebotomist complete a blood draw in 10 minutes. The supplies for each draw cost 4, and the phlebotomist earns 20 per hour. The phlebotomy lab is designed to accommodate 20,000...

A new computer lets a phlebotomist complete a blood draw in 10 minutes. The supplies for each draw cost
4, and the phlebotomist earns
20 per hour. The phlebotomy lab is designed to accommodate 20,000 draws per year. Its rent is
80,000 per year. What is the marginal cost of a blood draw? What principle does your calculation illustrate?