bellfont company produces door stoppers. august production costs are below. door stoppers produced 70000 direct material (variable) 20000, direct labor(variable)40000, suppliers(variable) 20000, supervision ( fixed)25100, depreciation (fixed) 23100, other (fixed) 5000. in september, bellfont expects to produce 100000 door stoppers. assuming no structural charges, what is bellfonts production cost per door stoppers in september.