Minden Co has current assets of $180,000 (cash: $20,000, accounts receivable: $70,000, inventory: $90,000), and long-term assets that had cost $400,000, with accumulated depreciation to date of $180,000. Sales were $500,000, and operating profit was $50,000. Tax was $20,000 and interest paid was $10,000. Their receivables turnover ratio was