In this market structure, product differentiation is evident. a monopoly

perfect competition

monopolistic competition

an oligopoly

Spartan systems reported total sales of $500,000, at a price of $20 and per unit variable expenses of $13, for the sales of their single product. total per unit sales $500,000 $20 variable expenses 325,000 13 contribution margin 175,000 $7 fixed expenses 120,000 net operating income $55,000 what is the amount of contribution margin if sales volume increases by 30%?