Sebastian is considering adding new items to his convenience store. He estimates that the cost of inventory will be $2,400. The remodeling expenses and shelving costs are estimated at $2,900. New item sales are expected to produce net cash inflows of $1,450, $2,200, $3,130, and $2,020 over the next four years, respectively. 

What is the pay back period for the project? 

Should Sebastian add new items to his store if he assigns a three-year payback period to this project? Why or why not? 

Please assume that CFs occur evenly throughout a year.