Olsen Outfitters Inc. believes that its optimal capital structure consists of $60\%$ common equity and $40\%$ debt, and its tax rate is $25\%.$ Olsen must raise additional capital to fund its upcoming expension. The firm will have $$1$ million of retained earnings with a cost of $r_s=10\%.$ New common stock in an amount up to $$10$ million would have a cost of $r_2=12\mathrm{.}5\%.$ Furthermore, Otsen ralse up to $$4$ million of debt at an interest rate of $r_d=9\%$ and an additional $$6$ million of debt at $r_d=13\%.$ The CFO estimates that a proposed expansion would require an investment of $$4\mathrm{.}8$ million. What is the WACC for the last dollar raised to complete the expansion? Round your answer to two decimal places.