An open economy represented by the following equations: C = 1000 + 0.9Yd I = 500 G = 300 T = 0.2Y X = 200 M= 100 + 0.22Y

Where C is consumption, Yd is disposable income, I is investment, G is government spending, Y is income, X is exports, and M is imports.

Calculate the following: a) The equilibrium value of Y, where planned demand equals planned supply in the goods market in an open economy; b) The value of the expenditure multiplier; c) The increase in Y if I increased to 600; d) The increase in G required for Y to rise to 5000;