Biotin Corp.'s current balance sheet reports the following stockholders' equity: 5% cumulative preferred stock, par value $100 per share; 2,500 shares issued and outstanding $250,000 Common stock, par value $3.50 per share; 100,000 shares issued and outstanding $350,000 Additional paid-in capital in excess of par value of common stock $125,000 Retained earnings $300,000 Dividends in arrears on the preferred stock amount to $25,000. If Biotin were to be liquidated, the preferred stockholders would receive par value plus a premium of $50,000. The book value per share of common stock is