Answer:
4.1 years
Step-by-step explanation:
The payback period is the time it takes the project to recover the initial investment required to carry it out.
We are not given any information about the actual yearly revenues and costs, but you give the average net cash flow per year, so we can use that amount to calculate the payback period:
the payback period = total investment / net cash flow = $11,500,000 / $2,779,548 = 4.137 ≈ 4.1 years