Oracle Corporation recorded total revenues of $50 billion and a cost of goods sold of $20 billion for 2023. The operating expenses were $20 billion, while the interest expense was $1 billion, and tax expense was $4 billion. The total assets of the company were reported to be $100 billion and total liabilities were $50 billion.

1. Calculate the gross profit margin.
2. Determine the operating profit margin.
3. Compute the interest coverage ratio.

Determine the return on equity (ROE).