Final answer:
To close the recessionary gap, the government would need to increase spending by $80 billion.
Step-by-step explanation:
In order to close the recessionary gap, the government would need to increase spending. The amount of increase in spending can be calculated using the formula:
Change in GDP = Multiplier x Change in Government Spending
Given that the economy is operating $400 billion below its natural level, we can use the multiplier to determine the change in government spending. The multiplier is calculated as:
Multiplier = 1 / (1 - Marginal Propensity to Consume)
Substituting the given marginal propensity to consume, we get:
Multiplier = 1 / (1 - 0.8) = 5
To close the recessionary gap of $400 billion, the government would need to increase spending by $80 billion.