The Tyler Oil Company's capital structure is as follows: The aftertax cost of debt is 12 percent; the cost of preferred stock is 15 percent; and the cost of common equity (ir the form of retained earnings) is 18 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's, an outside consultant has suggested the following modifications. Under this new and more debt-oriented arrangement, the aftertax cost of debt is 14.8 percent, the cost of preferre stock is 9 percent, and the cost of common equity (in the form of retained earnings) is 18.0 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