Financial Summary for Delta Airlines 2023:

Financial Metric	Amount
Total Revenue	$55 million
Cost of Services	$32 million
Operating Expenses	$13 million
Interest Expense	$2 million
Tax Expense	$3 million
Total Assets	$80 million
Total Liabilities	$45 million

1. Calculate the operating profit margin.
2. Determine the net profit margin.
3. Compute the debt-to-equity ratio.

Calculate the return on assets (ROA).