Answer:
Profit from sale of special order of 4,000 units increase by $14000
Step-by-step explanation:
given data 
order = 4000 units 
Sales = $ 190,000 
Cost of Goods Sold = 45,000 
Gross Margin = $45,000
Sales price per unit = $15
solution
as we know that Elkhorn has excess capacity
so sales of 4000 additional units would not affect current sales of 10,000 units
and by production of excess 4000 units fixed cost would not increase
so Variable cost per unit will be 
Variable cost per unit = 

 Variable cost per unit = $11.5 
so 
Profit per unit will be 
Profit per unit = Sales price - Variable cost 
Profit per unit = $15 - $11.5 
Profit per unit = $3.5 
 so 
Profit from sale of special order of 4,000 units increase as = 4000 × $3.5
Profit from sale of special order of 4,000 units increase by $14000