Company: Berkshire Hathaway Inc.

Berkshire Hathaway Inc. disclosed its financial results for the fiscal year ending December 31, 2023. The company reported total revenue of $350 billion, with a cost of goods sold (COGS) of $200 billion and operating expenses of $100 billion. Net income amounted to $50 billion. Based on this data: a) Calculate the gross profit margin. b) Determine the operating profit margin. c) Compute the net profit margin. d) Evaluate the return on assets (ROA) if the company's total assets amount to $800 billion.