The organisers of the next London Marathon ordered flags and jackets for the voluntoers. The manufacturer has 750m2 of cotton fabric, and 1000m2 of polyester fabric. Every flag needs 1m2 of cotton and 2m2 of polyester. Every jacket needs 1.5m2 of cotton fabric and 1m2 of polyester. The organisers will pay 5 for every flag, and 4 for every jacket. (a) Formulate the optimisation problem to maximise the sale for the manufacturer. [4 marks] (b) Solve the optimisation problem using the graphical method. [6 marks ]