SoftSoap Corporation is a large consumer product firm that reported after-tax operating income of \($600\) million in a recent financial year. At the beginning of the year, the firm reported book value of equity of \($4\) billion and book value of debt of \($1\) billion. The market value of equity was \($8\) billion, the market value of debt was \($1\) billion, and the firm had a cost of equity of 11% and an after-tax cost of debt of 4%. If the firm is in stable growth, expecting to grow 4% a year in perpetuity, estimate the correct value-to-book value ratio for the firm.