Final answer:
To move to potential GDP, the economy needs a change in autonomous spending of approximately $186.99 billion.
Step-by-step explanation:
To determine the change in autonomous spending needed for the economy to move to potential GDP, we can use the formula:
Change in GDP = (1 - MPC) * Change in Autonomous Spending
Given that Potential GDP equals $400 billion and the current GDP is $450 billion, the change in GDP needed is $400 billion - $450 billion = -$50 billion.
Plugging this value into the formula, we have:
-$50 billion = (1 - 0.73) * Change in Autonomous Spending
Simplifying the equation, we can find that the change in autonomous spending is approximately $186.99 billion (rounded to two decimal places).