Wexxon Plc currently makes four products for sale on the local market. Details of the four products and relevant information are given below for one period: Product Axxon Beach Capal Delta Output in units 120 100 80 120 Cost per unit: Direct material $40 $50 $30 $60 Direct labour $28 $21 $14 $21 Machine hours (per unit) 4 3 2 3 The four products are similar and are usually produced in production runs of 20 units and sold in batches