How to determine dollar amount of finished goods inventory?

sales $100,000

Cost of goods manufactured 54,000

Direct material purchased 78,000

Factory overhead 18,000

Work in process-Jan 1 58,000

work in process-Dec 31 28,000

Direct Material -Dec 31 18,000

Finished Goods Inventory- Dec 31 42,000

Net income 30,000

Direct materials used 58,000

Cost of Goods Sold 52,000