Increased by $170,000./Net working capital is the difference between current assets and current liabilities. Because current assets went up $120,000 and current liabilities down by $50,000, the net effect is an increase in net working capital of $170,000.
Before change Change After Change
Currect assets $ 500,000 $ 120,000 $ 620,000
Current liabilities 300,000 (50,000) 250,000
Net working capital $ 200,000 $ 370,000