please solve and explain

Fims HL and 1. ate iteentical except for their financial leverage ratios and the interest rates they pay on debt. Each has $25 miltion in invested cepital, has $3.75 million of Exr, and is in the 25% federal-plus-state tax bracket. Firm HL, however, has a debt-to-capital ratio of 55% and pays 12% interest on its debt, whereas LL has a 25%. dete-to-capital ratio and pays only 10% interest on its debt. Neither firm uses preferred stock in its capital structure. a. Calculate the return on invested capital (ROIC) for each firm. Round your answers to two decimal places. ROIC for firm 42= HOiC for firm HL: b. Calculate the rate of return on equity (ROE) for each firm. Round your answers to two decimbl places. ROE for firm Lle: HOE for firm HL: c. Observing that Hi has a higher Rot, Li's treosurer is thinking if ralsing the debt-to-copital retio from 25% to 60% even though that would increase 1 iss interest rate on all detht to 15\%, colculate the riew Rot for LL. Found your answer to two decimel paces