what excel formula should i use to solve this problem?? Mark is using the modified internal rate of return (MIRR) when evaluating investment opportunities. He is able to reinvest cash flows received from the investment at an annual rate of 8.00 percent. The investment will produce the same after-tax cash inflows of 547,900 per year at the end of the year for 5 years. What is the MIRR of an investment if the initial costs are $2,211,100