Roka Company has the following items in its inventory on August 1 Serial Number Cost 6X6A1 $ 10 300 6Y6MS 11.100 6B6D8 8.900 6R7R5 12.000 The company uses the specific-unit-cost method for costing inventory. During August it sold units 6X6A1 and 68608 for $31.000 each and purchased unit 6A7M6 for $25.000 Calculate the gross margin for the month of August The gross margin for the month of August is $