Our company is thinking about updating one of its production facilities and believes that by investing $21 million today, it will be able to increase to companies cash flow's by 3.5 million per year for the next 9 years.

It expects an additional cash flow of $6 million at the end of that period, as it plans to resell some of its used production equipment at that time. The required rate of return on this project is 10%.

What is the internal rate of return of this potential investment?