If sales increase by $80,000, operating income will increase by ( Round interim calculations to two decimal places and the final answer to the nearest whole dollar.) $30,588 $32,000 $48,000 $57.872 Sparkle Jewelry sells 800 units resulting in $9,000 of sales revenue, $3,000 of variable costs, and $1,500 of fixed costs. Contribution margin per unit is . (Round the final answer to the nearest cent.)