A firm has determined its cost of each source of capital and the percentage of each source making up the​ firm's capital​ structure: ModifyingAbove and below Start 2 By 1 Matrix 1st Row 1st Column Bold Start 2 By 1 Matrix 1st Row 1st Column Capital Structure 2nd Row 1st Column Source of Capital Proportions After minus Tax Cost EndMatrix 2nd Row 1st Column Start 3 By 1 Matrix 1st Row 1st Column Long minus term debt 40 % 6 % 2nd Row 1st Column Preferred stock 10 11 3rd Row 1st Column Common stock equity 50 15 EndMatrix EndMatrix with brackets The weighted average cost of capital is​ ________.