Answer and Explanation:
a. The computation of the cost of goods sold is shown below:
Beginning inventory               $32,800
Add: Net purchase
Purchase $248,000
Less: Purchase discount -$6,800
Less: Purchase returns -$10,800
Add: Freight in $18,600
Total net purchased               $249,000
Less: ending inventory          -$40,800
Cost of goods sold                 $241,000
2. The year end adjusting entry is 
Cost of goods sold Dr $241,000
Ending inventory  Dr $40,800
Purchase discount Dr $6,800
Purchase returns Dr $10,800
             To Beginning inventory $32,800
             To Purchase $248,000
             To freight in $18,600
(Being the cost of goods sold is recorded)