In 2023, Alaska Airlines recorded total revenues of $75 million and a cost of services of $45 million. The operating expenses were $17 million, while the interest expense was $3 million, and tax expense was $4 million. The total assets of the company were reported to be $95 million and total liabilities were $55 million.

1. Calculate the gross profit margin.
2. Determine the operating profit margin.
3. Compute the interest coverage ratio.
4. Determine the return on equity (ROE).