A company is preparing its financial statements and needs to complete the following calculations using the given data:
Beginning Inventory: $60,000
Ending Inventory: $90,000
Purchases during the year: $400,000
Sales Revenue: $600,000
Sales Returns and Allowances: $30,000
Operating Expenses: $150,000
Interest Expense: $20,000
Income Tax Rate: 25%

The company uses the periodic inventory system. Calculate the Cost of Goods Sold (COGS).