Caterpillar Inc. reported the following for 2023: total revenue of $70 billion, cost of goods sold of $40 billion, operating expenses of $20 billion, interest expense of $3 billion, and tax expense of $4 billion. The total assets were $120 billion, and total liabilities were $50 billion.

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

Determine the debt-to-equity ratio.