please explain where the 12 comes from in the incremental costs section. i got the answer from an answer key but I do not understand how to get 12 in the second row.

PS Relevant Costs for Decision Making Sound Inc. reported the following results from the sale of 24.000 radios: Sales $528,000 Variable manufacturing costs 288,000 Fixed manufacturing costs 120,000 Variable selling costs 52,800 Fixed administration costs 35,200 Rhythm Co. has offered to purchase 3,000 radios at $16 eachSound estimates approximately 5.000 units could be made with the capacity currently available in the factory. The owner of Sound is in favor of it would be profitable because no variable selling costs will be incurred. The plant manager is opposed because his full cost of production is $17 What would the change in profit be if the special order is accepted? Incremental Revenue Incremental Costs | incremental Income Total (3,000 UNITS) 16.3,000 = 48,000 12-3000 - 123000 36.000 4.3000- 12.000