Merck & Co., Inc. disclosed the following financial data for the year ending December 31, 2023:

• Total Revenue: $70 billion
• Cost of Goods Sold (COGS): $25 billion
• Operating Expenses: $20 billion
• Other Income: $5 billion
• Tax Expense: $10 billion

a) Calculate the gross profit. b) Determine the operating profit. c) Compute the net profit before tax. d) Calculate the net profit after tax, assuming a tax rate of 20%.