Ruben intends to sell his customers a special roundtrip airline ticket package. He is able to purchase the package from the airline carrier for $140 each. The roundtrip tickets will be sold for $230 each and the airline intends to reimburse Ruben for any unsold ticket packages. Fixed costs include $5,557 in advertising costs. For every $27,000 of ticket packagessold, operating income will increase by________.