The following model describes an imaginary economy (all the monetary values are in GHe million). Y =C+I+G+X-M (Income identity) C = 2000 + 0.8Yd (Consumption) Yd = Y -T (Disposable income) T = 400 + 0.25Y (Tax function) I = 500 (Investment expenditure) G = 800 (Government expenditure) X = 305 (Exports) M = 200 + 0.1Y (Imports function) (a) Calculate the economy's equilibrium national income (10 Marks) (b) Find the size of the multiplier (5 Marks) (c) Calculate the total consumption expenditure