Fast Track Auto produces and sells an auto part for $60 per unit. In 2017, 120,000 parts were produced and 75,000 units were sold. Other information for the year includes: Direct materials $20 per unit Direct manufacturing labor $5 per unit Variable manufacturing $3 per unit costs Sales commissions $7 per part Fixed manufacturing $760,000 per year costs Administrative expenses, all $270,000 per fixed year What is the inventoriable cost per unit using variable costing