STU Corporation has the following financial data for the year 2023:

• Net Sales: $500,000
• Cost of Goods Sold: $300,000
• Administrative Expenses: $50,000
• Selling Expenses: $60,000
• Interest Expense: $10,000
• Tax Expense: $15,000

Requirements:

1. Prepare an income statement.
2. Calculate the gross profit margin.
3. Calculate the operating profit margin.
4. Compute the net profit margin.
5. Analyze the impact of a 10% increase in sales on the net profit margin.