I know the answers I just need detailed step-by-step instructions.

A company keeps 20 days of materials inventory on hand to avoid shutdowns due to materials shortages. Carrying costs average $4,000 per day. A competitor keeps 10 days of inventory on hand, and the competitor's carrying costs average $2,000 per day.

20. What are the value-added costs are? (Ans: $0)

21. What are the non-value-added costs? (Ans: $80,000)