Final answer:
For a closed economy with the given figures, the private saving is calculated as $1 trillion, and the national saving, which includes the government's surplus, is $2 trillion.
Step-by-step explanation:
In a closed economy, to find private saving, we subtract taxes and consumption from GDP:
Private Saving = GDP - Consumption - Taxes
Private Saving = $11 trillion - $7 trillion - $3 trillion = $1 trillion.
For national saving, we must consider both private saving and the government surplus. National saving is the sum of private saving and the government surplus:
National Saving = Private Saving + Government Surplus
National Saving = $1 trillion + $1 trillion = $2 trillion.
Therefore, the private saving is $1 trillion and the national saving is $2 trillion.