I need help figuring out the Less traceable fixed costs calculation. I have the answer below this I just need to see how to get those numbers

Problem 5 -- Bethel Corporation provided the following income statement for two of its divisions: North and South. Required: The home office allocated common fixed costs of $18,000 to North and $2,000 to South. Prepare a segment margin income statement. Segment Margin Income Statement for Bethel Corporation