Consider a closed economy in which GDP equals $15 billion, consumption equals $9 billion, government purchases equal $2 billion, and tax revenue equals $1 billion. Use this information to answer the following questions:
a) What is investment equal to in this economy?
b) What is national saving equal to in this economy?
c) What is public saving equal to in this economy?
d) What is private saving equal to in this economy?
e) What are net exports equal to in this economy?