Explain the math to how they solved the journal entries pls

Proud Company and Slinky Company both produce and purchase equipment for resale each period and frequently sell to each other. Since Proud Company holds 60 percent ownership of Slinky Company, Proud's controller compiled the following information with regard to intercompany transactions between the two companies in 2005 and 20x6: Year 20x5 20X5 20x6 Produced by Proud Company Slinky Company Proud Company Slinky Company Sold to Slinky Company Proud Company Slinky Company Proud Company Percent Resold to Nonaffiliate in 20x5 20x6 60% 40% 30 50 90 25 Cost to produce $100,000 70,000 40,000 200,000 Sale Price to Affiliate $150,000 100,000 60,000 240,000 20x6 Required: a. Prepare the consolidation entries required at December 31, 20X6, to eliminate the effects of the inventory transfers in preparing a full set of consolidated financial statements. (If no entry is required for a transaction/event, select "No journal entry required" in the first account field.) No Entry Accounts Debit Credit A 1 20,000 Investment in Slinky Cost of goods sold 00 20,000 B 2 12,600 8,400 Investment in Slinky NCI in NA of Slinky Cost of goods sold Inventory 15,000 6,000 3 Sales 60,000 Cost of goods sold Inventory 58,000 2,000 D 4 Sales 240.000 Cost of goods sold Inventory OOO 210,000 30,000