PQR Ltd. presents the following financial information:

• Cash and cash equivalents: $100,000
• Accounts receivable: $120,000
• Inventory: $80,000
• Total current liabilities: $150,000
• Total assets: $800,000
• Total liabilities: $400,000
• Net income: $100,000

Compute: a) Acid-test ratio b) Inventory turnover c) Return on total assets d) Profit margin ratio