Selected year-end financial statements of Cabot Corporation follow. (All sales were on credit; selected balance sheet amounts at December 31, 2016, were inventory, $46,900; total assets, $249,400; common stock, $88,000; and retained earnings, $28,156.)

CABOT CORPORATION Income Statement For Year Ended December 31, 2017
Sales	$	450,600
Cost of goods sold		298,250
Gross profit		152,350
Operating expenses		99,600
Interest expense		4,700
Income before taxes		48,050
Income taxes		19,356
Net income	$	28,694

CABOT CORPORATION Balance Sheet December 31, 2017
Assets				Liabilities and Equity
Cash	$	8,000		Accounts payable	$	16,500
Short-term investments		8,400		Accrued wages payable		3,200
Accounts receivable, net		31,200		Income taxes payable		4,100
Notes receivable (trade)*		5,500
Merchandise inventory		30,150		Long-term note payable, secured by mortgage on plant assets		69,400
Prepaid expenses		2,500		Common stock		88,000
Plant assets, net		152,300		Retained earnings		56,850
Total assets	$	238,050		Total liabilities and equity	$	238,050

1) Compute the days' sales in inventory.

2) Compute the debt-to-equity ratio.

3) Compute the times interest earned.

4) Compute the profit margin ratio.