Answer and Explanation:
Given that
Consumption function C = 200 + 0.9Y
Investment I = 300
Aggregate expenditure AE = C + I
Equilibrium AE = Y
Based on the above information
a. The level of equibrium income is
Y = AE = C + I
Y = 200 + 0.9Y + 300
0.1Y = 500
Y = 5000
b. The value of the investment multiplier is
= 1 ÷ (1 - MPC)
= 1 ÷ (1 - 0.9)
= 10
c. The change in the level of equilibrium income if investment increases by 10 is
Y = 200 + 0.9Y + 310
0.1Y = 510
Y = 5100
Change is
= 5,100 - 5,000
= 100