3. (30 points) Consider an economy which is described by the following equations: 0 = 500 + 0750/ T) I = 1000 507\" (M/P)d = Y 200?\" G = 1000 T = 1000 M = 6000 P = 2 where Y denotes the aggregate income, T denotes taxes, G de- notes government expenditures, 0 denotes consumption, I denotes investment, M denotes the money supply, P denotes the price level, and r is the interest rate. Furthermore, suppose that the cash-to- deposit ratio is equal to 0.2, while the reserve-to-deposit ratio is equal to 0.1. (a) Derive the equations for the IS and LM curves, and find the equilibrium in this economy. [7.5]