Managerial Accounting: Computing Inventory balances

I am stuck on this question: Calculate the product cost per unit and the total cost of the 2,100 units in ending inventory using absorption costing and variable costing. An explanation would be great. Thank you

Finished Goods Inventory:

Beginning Balance, in units 500

Units Produced 3,100

Units sold (1,500)

Ending Balance 2,100

Production Cost

Variable Mfg costs per unit $ 65

Total fixed Mfg costs 40,300