need help finding cost of goods sold and ending inventory

PA 13. LO 6.5 Grainger Company produces only one product and sells that product for $100 per unit. Cost information for the product is: Selling expenses are $4 per unit and are all variable. Administrative expenses of $20,000 are all fixed. Grainger produced 5,000 units; sold 4,000; and had no beginning inventory. A. Compute net income under i. absorption costing ii. variable costing B. Reconcile the difference between the income under absorption and variable costing