Berkshire Hathaway Inc. 2023 Financials:

Financial Metric	Amount
Total Revenue	$250 billion
Cost of Goods Sold	$150 billion
Operating Expenses	$60 billion
Interest Expense	$6 billion
Tax Expense	$12 billion
Total Assets	$650 billion
Total Liabilities	$300 billion

1. Calculate the operating profit margin.
2. Determine the net profit margin.
3. Compute the debt-to-equity ratio.
4. Calculate the return on assets (ROA).