Waterloo Storage Products makes a four$-$drawer plastic storage cabinet on casters meant for use in garages and workshops. Each cabinet sells for $$45.$ Data for last year's operations follow:

$\backslash$table$[[$Units in beginning inventory,$0],[$Units produced,$21,600],[$Units sold,$19,800],[$Units in ending inventory,$1,800],[,],[$Variable costs per unit:,$10],[$Direct materials,$12],[$Direct labour,$4],[$Variable manufacturing overhead,$6],[$Variable selling and administrative,$