A market is described by the following supply and demand curves:

Supply: P=0.25Q

Demand: P=300-0.75Q

(a) Solve for the equilibrium price and quantity and calculate the total economic surplus with a diagram.

(b) Suppose government sets a price floor of $90. With the price regulation, calculate with a diagram the sizes of shortage (or surplus), consumer surplus, produce surplus and deadweight loss.

(c) Instead of a price floor, government regulates the price by a price ceiling of $90. Predict the change of market efficiency if the government imposes a price ceiling of $90.

(d) Instead of a price control, government levies a $20 excite tax on producers. Formulate the new supply curve and solve for the new equilibrium price and quantity. Calculate with a diagram the tax revenue and the tax incidences for both producers and consumers. Discuss how buyers and sellers share the tax burden by applying relevant theories and an appropriate diagram.