You have been given the following data for a company's balance sheet:

• Cash and cash equivalents: $20,000
• Accounts receivable: $30,000
• Inventory: $40,000
• Property, plant and equipment: $200,000
• Accumulated depreciation: $50,000
• Accounts payable: $50,000
• Long-term debt: $100,000
• Shareholders' equity: $90,000

Calculate the following ratios for the company:

a) Current ratio

b) Quick ratio

c) Debt-to-equity ratio

d) Return on equity (ROE)