Wu Systems has the following balance sheet. Assume that all current assets are used in operations. How much net operating working capital does the firm have?

Cash	$	50		Accounts payable	$	250
Accounts receivable		680		Accruals		170
Inventory		570		Notes payable		480
Current assets	$	1,300		Current liabilities	$	900
Net fixed assets		1,000		Long-term debt		620
				Common equity		280
				Retained earnings		500
Total assets	$	2,300		Total liab. & equity	$	2,300

a. $1,720

b. $420

c. $2,200

d. $880

e. $400