Consider a closed economy that is characterized by the following equations: Y = C+I+G C = 900 + 0.5(Y - T) I = 750 - 30r T = 800 G = 1200 Ma = Ms Ms = 1500 Mt = 0.7Y Msp = -80r (9) Where Y is the GDP, C is private consumption expenditure, I is the Investment expenditure, G is government expenditure, T is tax revenues, My is money supply, M, is transaction demand for money, Msp is the speculative demand for money and r is the interest rate (in % points). a) Derive (Ma/P) the demand for real money balances equation (where P is the aggregate price level.) b) Derive the IS and LM equations of the economy (Express Y as a function of r and assume P is fixed at 1.0.) c) Calculate the short-run equilibrium values of Y and r in the economy