A small engineering firm has three senior designers available to work on the firm's three current projects over the next two weeks. The firm's manager has developed the following table of quality scores, which shows each designer's design quality on each type of project, out of 100. Also shown is an estimate of the time required for each project. Project 2 Designer 1 2 3 Time 1 90 60 70 70 80 70 80 50 3 25 50 40 85 Each designer has 80 hours available over the next two weeks. Assume that more than one designer can work on a project. The manager wants to assign designers to projects in order to maximise the sum of the quality scores assigned. Formulate the algebraic model for this problem by writing down the decision variables, objective function and constraints, to maximise the sum of the quality scores assigned