Can someone tell me where the 2.4 is coming from in the solution?

2. W.V. Trees, Inc. has a debt-equity ratio of 1.4. Its WACC is 10 percent, and its cost of debt is 9 percent. The corporate tax rate is 33 percent. What is the firm's unlevered cost of equity capital? A. 12.38 percent B. 12.79 percent C. 13.68 percent D. 14.10 percent E. 14.45 percent WACC-0.10-(1/2.4) Re+ (1.4/2.4) (0.09) (1-033); RE-0.15558 RE-0.15558-Ru(Ru 0.09)(1.4) (1 - 0.33); Ru- 12.38 percent