Variable costing system Product X Product Y Product Z Total k k k k Sales 100k units at 15 1,500 80k units at 25 2,000 120k units at 10 1,200 4,700 Total variable costs 1000 1200 1320 3520 Contribution margin 500 800 (120) 1,180 Total fixed costs 250 400 270 920 Net profit 250 400 (390) 260 (Table 2.2)