What is the contribution margin per unit? What is the contribution margin ration? What is the variable expense ratio? if sales increase to 1.031. What would be the increase in net operating income? If sales decline to 900 units. what would be the net operating income? If the selling price increases by $1.50 per unit and the soles volume decreases by 100 units. what would be the net operating? If the variable cost per unit increases cry $.50 spending on advertising increases by $1, 000. and unit sales increase by 250 units. what would be the net operating income? What is the break-even point in unit sales