Corporate Taxes. Montgomery Enterprises, Inc., had operating earnings of $280,000 for the year just ended. During the year the firm sold stock that it held in another company for $180,000, which was $30,000 above its original purchase price of $150,000, paid 1 year earlier. a.) What is the amount, if any, of capital gains realized during the year? b.) How much total taxable income did the firm earn during the year? c.) Use the corporate tax rate schedule given in Table 1.4 to calculate the firms total taxes due. d.) Calculate both the average tax rate and the marginal tax rate on the basis of your findings.