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This answer calculates normal spoilage as 3% of the number of baseballs completed, not of the baseballs that pass inspection.
This is the cost of good baseballs that were produced.
This is the amount of normal spoilage.
The first thing that we need to do is to determine how many units are abnormal spoilage. Since 3% of the good units is considered normal, this is 60 baseballs (3% × 2,000 units passing inspection). Since there were 100 spoiled units and 60 is the normal spoilage, abnormal spoilage was 40 units. After this, we need to determine the cost per unit. Remember that we allocate costs to the spoiled units. Because there was no beginning or ending work in progress, we can treat all of the costs the same, using a total cost of $1,155. This is allocated to each of the 2,100 units produced, giving a rate of $.55 per unit. This is the cost that is allocated to the 40 abnormally spoiled units, giving a total cost of $22 for abnormal spoilage.