please get it right!!!!

3.12 points Delta Corporation has the following capital structure Cost (aftertax) Weights Cost Debt (Ka) Preferred stock (Kp) Common equity (Ke) (retained earnings) Weighted average cost of capital (Ka) 7.1% 8.6 2.1 15% 25 60 1.07% 2.15 7.26 10 48% a. If the firm has $27 million in retained earnings, at what size capital structure will the firm run out of retained earnings? (Enter your answer in millions of dollars (e.g., $10 million should be entered as "10")) Capital structure size (X) million b. The 7.1 percent cost of debt referred to earlier applies only to the first $9 million of debt. After that the cost of debt will go up. At what size capital structure will there be a change in the cost of debt? (Enter your answer in millions of dollars (e.g., $10 million should be entered as "10").) Capital structure size (Z) million