CHEG314- ENGINEERING ECONOMICS Tutorial 8 PROBLEM 1: RIOC/MIRR A company had the cash flows shown for one department. a. Calculate the internal rate of return. 15% per year. Calculate the external rate of return using the MIRR method with a reinvestment rate of 15% per year and a borrowing rate of 8% per year. c. Year Flow, 0 75,000 1 35,000 2 74,000 ,000