a. What is the CW, when i = 10% per year, of $1,500 per year, starting in

Question:

a. What is the CW, when i = 10% per year, of $1,500 per year, starting in year one and continuing forever; and $10,000 in year five, repeating every four years thereafter, and continuing forever?
b. When i = 10% per year in this type of problem, what value of N, practically speaking, defines "forever"?