Suppose that a market is described by the following supply and demand equations: QS=10P Q = 150 20P where QS is the quantity supplied measured in units, QP is the quantity demanded measured in units, and P is the price measured in dollars. 7.5 5.5 S P S D -Q 150 40 a. Solve for the equilibrium price and quantity in the market. b. Calculate the consumer surplus, producer surplus, and the total surplus at the equilibrium.