You will pay 20 annual payments of 8000 starting one year from today. In year 21, you will receive a pension for the following fifteen years. The discount rate used by the company to calculate your pension is 6%. What is the size of your pension? and if you could take a one-time lump sum payment 25 years from today instead of the pension, how would the equivalent lump sum payment have to be?

What makes me confused is mainly that how I should view the 20 years' payment. Is that a simple annual payment of 160000 in total or should I consider the 6% interest rate while calculating its future value? Please provide explanation THX!!! I'd like to know how I'm supposed to think it through :)