The Martian Corporation, a space vehicle development company, is starting a new division that will develop the next-generation launch missile engine configuration. Use a hand application of the MIRR method to determine the EROR for the estimated net cash flows (in $1000 units) of $-40,000 in year 0, $11,000 in years 1 through 7, and $-2,000 in year 8. Assume a borrowing rate of 8% and an investment rate of 20% per year.

The external rate of return is %.?