The Tyler Oil Company's capital structure is as follows: The aftertax cost of debt is 7 percent; the cost of preferred stock is 10 percent; and the cost of common equity (in the form of retained earnings) is 13 percent. a-1. Calculate Tyler Oil Company's weighted average cost of capital. (Round the final answers to 2 decimal places.) As an alternative to the capital structure shown above for Tyler Oil Company, an outside consultant has suggested the following modifications. Under this new and more debt-oriented arrangement, the aftertax cost of debt is 8.8 percent, the cost of preferred stock is 10.5 percent, and the cost of common equity (in the form of retained earnings) is 15.5 percent. a-2. Calculate Tyler's weighted average cost of capital. (Round the final answers to 2 decimal places.) b. Which plan is optimal in terms of minimizing the weighted average cost of capital? Plan 1 Plan 2