An economy is described by the following equations: Desired consumption: C" = 140 + 0.5(Y - T) - 500r. Desired investment: / = 80 - 500r. Government purchases: G = 100. Government taxes: T = 90. Real money demand: L = 0.5Y - 1100r. Nominal money supply: M = 1,320. Full-employment output: Y = 500. Assume that the expected inflation rate is zero so that money demand depends on the real interest rate