A milling/ refining firm produces one unit of waste for each unit of milled/ refined product. The firm disposes of the waste by releasing it into the atmosphere. The inverse demand curve for the refined product (also the MB curve) is P=24-Q, where Q is the quantity of refined product consumed and P is the price that consumers. The inverse supply curve (also the MPC) for refining is MPC=2+Q. The marginal external cost, when the firm releases Q units of waste, is MEC=0.5Q

Calculate the equilibrium price and quantity for the refined product when the firm does not account for externality?