Linear Programming revision Q.

Dolly Trolleys manufacture trolleys for a chain of supermarkets. Demand for trolleys is buoyant, so all production can be sold. Two models are produced by Dolly - the streamline and the standard. The streamline has 3 wheels and the standard has 4 wheels. The daily availability of wheels is limited to 240. Dolly works a single 8-hour shift per day. There are 2 stages of manufacture for trolleys, fabrication an spraying. Spraying takes 24 minutes for each streamline trolley and 10 minutes for each standard, and frabrication takes 30 minutes for each streamline trolley and 20 minutes for each standard. three identical machines are available for fabrication, which can be used for either type of trolley(orboth). Spraying is carried out manually by one person per trolley, and there are two staff available for this process. The profit from seling a streamline trolley is £20 and for a standard trolley is £18. No more than 15 trolleys can be produced per hour because of storage limitations on work in progress.

Solve how the above problem can be formulated as a linear programme and derive the optimal solution to the problem, calculating exact values for all your variables.

Any help identifying and formulating the constraints?

(s=streamline, r=standard)

Wheel limitations: 3s + 4r (less than or equal) 240

Labour : 54s + 30r (less than or equal) 480 (mins)

What else? Are they correct?

Thank you. (hopefully this is in the right section)