Readymix Ltd Readymix Ltd manufactures three products: Product RR, Product DD and Product MM. The contribution per unit of the respective products is as follows: Product RR Contribution per unit 420 Product DD Product MM 320 620 The manufacture of these products involves two processes: Process Ready and Process Mix. The processing time requirements of each product (in hours) are as follows: Process Ready Process Mix Product RR 25 25 35 Product DD 50 40 Product MM 40 55 The monthly processing time of Process Ready and Process Mix is limited to 50,000 hours and 80,000 hours respectively. The sales of Product RR are limited to 900 units per month due to regulatory restrictions. The objective of the company is to maximise contribution.