Adams Furniture receives a special order for $10$ sofas for a special price of $$5,400.$ The direct materials and direct labor for each sofa are $$110.$ In addition, supervision and other fixed overhead costs average $$130$ per sofa.

a$1.$ What is the impact on operating income from accepting the special order?

Operating income would $($increase$/$decrease$)$ by $$\_\_\_\_\_\_\_\_\_$ per sofa.