An economy is operating with output $400 billion above its natural level, and fiscal policymakers want to close this expansionary gap. The central bank agrees to adjust the money supply to hold the interest rate constant, so there is no crowding out. The marginal propensity to consume is 4/5, and the price level is completely fixed in the short run. To close the expansionary gap, the government would need to spending by $ billion.

reduced by $80 billion

Explanation:

An expansionary gap is when the actual output is more than the potential output. From the question, we are told that an economy is operating with output $400 billion above its natural level, and fiscal policymakers want to close this expansionary gap and that the central bank agrees to adjust the money supply to hold the interest rate constant, so there is no crowding out.

We are also given the marginal propensity to consume is 4/5, and told that the price level is completely fixed in the short run.

To close the expansionary gap, the government would need to reduce its spending. To solve this, we have to calculate the multiplier. This will be:

Multiplier = 1/(1 - MPC)

= 1/(1 - 4/5)

= 1/1-0.8

= 1/0.2

= 5

Therefore, the government expenditure or spending will be reduced by:

= $400 billion/5

=$80 billion