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Q4 An open economy presents the following data. The intercept of the consumption

ID: 1159810 • Letter: Q

Question

Q4

An open economy presents the following data.

The intercept of the consumption function is 4700.

The marginal propensity to save (MPS) is 0.25.

There are no tax collections in this economy (we are assuming this because we have not yet covered the details of tax calculations in this course).

Government expenditure is 10,000.

Autonomous investment is 6,000.

The marginal propensity to invest is 0.15.

Autonomous exports are 5,000.

Autonomous imports are 3,000.

The marginal propensity to import is 0.1.

Using this information, answer the following 4 parts of Question 4.

Calculate the equilibrium level of GDP.

Calculate the multiplier in this economy.

Now suppose that the MPS rises to 0.4. Calculate the new multiplier in this economy.

Given the change in the MPS to 0.4, calculate the new equilibrium level of GDP.

Explanation / Answer

Consumption function: C = 4,700 + 0.75Y [Since MPS = 0.25, MPC = 1 - MPS = 1 - 0.25 = 0.75]

Investment function: I = 6,000 + 0.15Y

Import function: M = 3,000 + 0.1Y

(a) In equilibrium, Y = C + I + G + X - M

Y = 4,700 + 0.75Y + 6,000 + 0.15Y + 10,000 + 5,000 - 3,000 - 0.1Y

Y = 22,700 + 0.8Y

(1 - 0.8)Y = 22,700

0.2Y = 22,700

Y = 113,500

(b) Multiplier = 1 / (MPS - MPI + MPM) = 1 / (0.25 - 0.15 + 0.1) = 1 / 0.2 = 5

(c) When MPS = 0.4, Multiplier = 1 / (0.4 - 0.15 + 0.1) = 1 / 0.35 = 2.86

(d) With MPS = 0.4, MPC = 1 - 0.4 = 0.6

Y = 4,700 + 0.6Y + 6,000 + 0.15Y + 10,000 + 5,000 - 3,000 - 0.1Y

Y = 22,700 + 0.65Y

(1 - 0.65)Y = 22,700

0.35Y = 22,700

Y = 64,857.14