Answer and Explanation:
a. The computation is shown below;
As we know that
Y/G = 1 ÷ (1-MPC)
Here
Y = $300 billion,
MPC = 0.75
So,
300 ÷ G = 1 ÷ 0.25
G = $75
So the government should rise the spending by $75 in order to close out the recessionary gap
So, the government should increase the spending by $30 to close the recessionary gap.