please show all work step by step

Problem 2. Given the following conditions, calculate the MAXIMUM annul interest rate for this company to borrow money if the after tax WACC cannot exceed an annual rate of 6.61% (Answer needs to be shown 2 decimal points of a percent as xxx%) 10-year Treaswre Bond Annual Rate of Return Stock Beta value- S&P500 Index Expected annual rate of return Marginal Income Tax Rate 3.00% 1.25 10.00% 35% 65% Proportion of Debt to Total Capital