Step 1: Allocate the $300,000 common costs to the two remaining product lines based on their relative sales. Stunner: $ 320 , 000 $ 320 , 000 $ 480 , 000 × $ 300 , 000 = $ 120 , 000 $320,000 $480,000 $320,000 ×$300,000=$120,000 Double-Set: $ 480 , 000 $ 320 , 000 $ 480 , 000 × $ 300 , 000 = $ 180 , 000 $320,000 $480,000 $480,000 ×$300,000=$180,000