I was having trouble trying to calculate the discount rate.

A project that provides annual cash flows of $18,000 for ten years costs $86,000 today. What is the NPV for the project if the required return is 9 percent? (Do not round intermediate calculations. Round your answer to 2 decimal places, e.g., 32.16.) NPV $ 29517.84 At a required return of 9 percent, should the firm accept this project? Accept Reject What is the NPV for the project if the required return is 21 percent? (Negative amount should be indicated by a minus sign. Do not round intermediate calculations and round your answer to 2 decimal places, e.g., 32.16.) NPV $ -13026.60 At a required return of 21 percent, should the firm accept this project? Accept Reject At what discount rate would you be indifferent between accepting the project and rejecting it? (Do not round intermediate calculations. Enter your answer as a percent rounded to 2 decimal places, e.g.. 32.16.) Discount rate %