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Problem 2: Fox Enterprises is considering six projects for possible construction over the next 4 years. Fox can undertake any of the projects partially completely. A partial undertaking of a project will prorate both the return and cash outlays proportionately. The expected (present value) returns and cash outlays for the projects are given in the following table. Project Year 4 2.4 Year 1 10.5 8.3 10.2 7.2 12.3 9.2 Cash outlay (S1000) Year 2 Year 3 2.2 12.6 9.5 14.2 5.6 10.5 10.1 8.3 6.9 3.1 4.2 5.0 6.3 Return (S1000) 32.40 35.80 17.75 14.80 18.20 12.35 7.8 Available funds (S1000) (a) Formulate the problem to determine the optimal project mix that maximizes the total return. (b) Suppose that if a portion of project 2 is undertaken, then at least an equal portion of projects 6 must be undertaken. Modify the formulation of the model