Firms HD and LD each has $30m in invested capital, $8m of EBIT, a tax rate of 30%. Firm HD has a D/E ratio of 50% with an interest rate of 9% on their debt. Firm LD has a debt-to capital ratio of 30%, however, pays 10% interest on their debt. Calculate the following:

a. Return on invested capital for each firm

b. Return on equity for each firm

c. If HDs CFO is thinking of raising the D/E from 50% to 60%, which will lower their interest rate further from 9% to 7%, calculate the new ROE for HD.