need answer to a and b

Canyon Tours showed the following components of working capital last year Accounts receivable Inventory Accounts payable Beginning of Year $ 28,000 9,300 14,400 End of Year $18,500 12,000 16,600 a. What was the change in net working capital during the year? (Use the minus sign to enter negative changes, if any) ANWC $ b. If sales were $37,100 and costs were $28,500, what was cash flow for the year? Ignore taxes. (Use the minus sign to enter negative changes, if any.) Cash flow $