Billabong Tech uses the internal rate of return (IRR) to select projects. Calculate the IRR for each of the following projects and recommend the best project based on this measure. Project T-Shirt requires an initial investment of $15000 and generates cash inflows of $8000 per year for 4 years. Project Board Shorts requires an initial investment of $25000 and produces cash inflows of $12000 per year for 5 years.