Superior Corporation sells a single product for $60 per unit, of which $36 is contribution margin. Fixed costs total $72,000 and net income before income tax is $28, 800. Determine the following The present sales volume in dollars. $ The break-even point in units. units The sales volume in units necessary to attain a net income before income tax of $39, 600. units The sales volume in units necessary to attain a net income before income tax equal to 20% of sales revenue. units The sales volume in units necessary to attain an after-tax net income of $43, 200 if the tax rate is 40% units