I need help with 2&3

I. What is an aggregate production function? II. Suppose that the economy of Nelsonia has a current GDP per capita of $40,000. What will be GDP per capita if the economy grows at the following rates? (show your work) A. 2% a year for 20 years? B. 4% a year for 20 years? C. 2% a year for 40 years? D. 4% a year for 40 years? III. If the average worker in Nelsonia is initially three times as productive as the average worker in Noslenia, and if productivity grows at a 2% rate in Nelsonia and a 5% rate in Noslenia, which country will have the most productive workers after the following periods? (show your work) A. 20 years? B. 30 years? C. 40 years