Harley worked for many years to save enough money to start his own residential landscape design business. The net cash flows shown are those he recorded for the first 6 years as his own boss. Find the external rate of return using the modified rate of return approach with a reinvestment rate of 15% per year and a borrowing rate of 8%. Additionally, after using the procedure, use the MIRR function to confirm your answer. The external rate of return is % per year. The spreadsheet function is Harley worked for many years to save enough money to start his own residential landscape design business. The net cash flows shown are those he recorded for the first 6 years as his own boss. Find the external rate of return using the modified rate of return approach with a reinvestment rate of 15% per year and a borrowing rate of 8%. Additionally, after using the procedure, use the MIRR function to confirm your answer. The external rate of return is % per year. The spreadsheet function is