Minden Co has current assets of $180,000 (cash: $20,000, accounts receivable: $70,000 inventory: $90,000), and long term assests that had cost $400,000, with accumulated depreciation to date of $180,000. Sales were $500000, and operating profit was $50,000. Tax was $20,000 and interest paid was $10,000. Their receivables turnover ratio was: a) 10.2 x b) 9.4X, c) 7.1x d) 5.6X e) none of the above