Answer:
Spending will decrease by $7.5 billion.
Explanation:
The value of MPC is 0.75.
There is a decline in net exports by $10 billion.
This means that the aggregate income will fall by $10 billion.
Change in spending
= [tex]change\ in\ income\ \times\ MPC[/tex]
= [tex]-10\ billion\ \times\ 0.75[/tex]
= - $7.5 billion
So, in the second round the spending will fall by $7.5 billion.