(IRR, payback, and calculating a missing cash flow) Mode Publishing

(IRR, payback, and calculating a missing cash flow) Mode Publishing is considering a new printing facility that will involve a large initial outlay and then result in a series of positive cash flows for four years. The estimated cash flows associated with this project are: 

If you know that the project has a regular payback of 2.5 years, what is the project's internal rate of return?