Question

Assume the following values of an economy.

Planned Investment (Ip) = $20

Autonomous Consumption (C ) = $30

Marginal Propensity to consume (MPC) = .9

What is the equilibrium income?

Y* = aggregate demand at the equilibrium level. (Consumption + investment)

Consumption function = autonomous consumption + mpc * Y.

C=30 + .9Y

AD = 30 + .9Y + 20 = 50 + .9Y

Y= 50 + .9Y.1Y = 50

Y = $500 is the equilibrium level of income.

What is the value of saving at equilibrium?

Savings = income - consumption at the equilibrium level of Y=500,

Consumption = 30 +.9 * 500 = $480

Savings = 500 - 480= 20

c. Does the saving and Investment Identity hold true at equilibrium income OR GDP?

Since planned investment = $20 which is equal to savings calculated, the saving investment identity holds true at equilibrium income.

2. In addition to the values given in question (1) above, assume the government increases its spending by $30 without raising taxes. The government can do this by borrowing from the private sector.

a. Based on this information calculate the new level of equilibrium income.

If Government expenditures = $30, Y = C + I + G

Y = 1/1-.09 * (30+20+30) Y = 800

b. Calculate the total value of consumption at equilibrium.

C = 30 + .9(800) = 750

c. Calculate the total value of saving at equilibrium.

Savings = I - C = 800 - 750 = 50

3. In addition to questions in (1 & 2) above, assume the government decides to raise autonomous taxes by $30 to balance its budget.

What is the new value of equilibrium income?

Y = 1/1-.9 (30-.9(30) +20+30) = 530

What is the value of the autonomous tax multiplier?

-.09/.01 = -9

c. What is the value of autonomous spending multiplier?

1/.1 = 10