A city engineer has estimated the annual toll revenues from a newly proposed highway construction over 20

Question:

A city engineer has estimated the annual toll revenues from a newly proposed highway construction over 20 years as follows:
An = ($2,000,000)(n)(1.06)n-1
n = 1,2, ...,20
To validate the bond, the engineer was asked to present the estimated total present value of toll revenue at an interest rate of 6%. Assuming annual compounding, find the present value of the estimated toll revenue.