The weekly supply for gasoline (in thousands of units) in Adelaide is given by the equation P=3+20, and the weekly demand is given by the equation P=9-Q, where P is the price in dollars. a) Find the equilibrium price and quantity. b) Calculate the weekly producer surplus. (2 marks) (2.5 marks) (2.5 marks) (2 marks) c) Calculate the weekly consumer surplus. d) Calculate the total weekly economic surplus generated at the market equilibrium.