Please show work. Need to understand all the steps.

Roberts Hardware is adding a new product line that will require an investment of $1,512,000. Managers estimate that this investment will have a 10-year life and generate net cash inflows of $320,000 the first year, $280,000 the second year, and $260,000 each year thereafter for eight years. Compute the payback period. Round to one decimal place. The payback is years