ABC Corporation's financial statements show the following:

• Cash: $160,000
• Accounts receivable: $90,000
• Inventory: $80,000
• Total current liabilities: $100,000
• Total assets: $800,000
• Total liabilities: $320,000
• Net income: $130,000

Compute: a) Quick ratio b) Inventory turnover ratio c) Return on equity d) Operating profit margin