10. Suppose that the demand for crude oil is given by: QD = 85 - 0.4P, where Qp is the quantity in millions of barrels per day and P is price per barrel in dollars. Suppose also that the supple for crude oil is given by: Qs = 55 + 0.6P a) Calculate equilibrium price and quantity in this market. b) Calculate the "excess demand" for crude oil if the market price is $15.00 per barrel. c) Calculate the "excess supply" of crude oil if the market price is $50.00 per barrel