the demand for tylenol, a chemical sold in a perfectly competitive market, is given by Q = 200 - 2P, where the quantity is measured in pounds. the private marginal cost is MC = 20 + 0.75Q, but producing this chemical also leads to an external marginal damage of MD = 5 + 0.25Q.

What is the equilibrium price and quantity of this good if the externality is ignored?