Instruction: To write a mathematical model, you need to do the followings: Define the decision variables and parameters (if they are shown by math symbols). %20 Write the objective function and constraints. The objective function and constraints in the mathematical model should be numbered. %60 Explain each line of the mathematical model after the model by referring to its number. %20 To Solve a mathematical model using Excel solver, the following parts should be done: Report each formula you have used in a cell of your spreadsheet model together with its address. For example, G8=SUMPRODUCT(C8F8,011:F11). %20 Report a screenshot of your spreadsheet model that has been solved and the optimal solution can be seen in it. Use meaningful labels in your spreadsheet model. %60 Report the screenshot of the solver window that has been filled out completely. %20 Question 3: 30 marks A construction company is considering a number of different development projects. The cash outflows that would be required to complete each project are indicated in the table below, along with the expected net present value of each project and available new money is each year (all values in millions of dollars). Year Project 3 1 4 5 2 10 Available new money 42 1 8 12 4 14 2 6 9 6 3 6 25 3 3 4 2 4 7 5 15 16 12 0 6 5 7 21 0 NPV 12 20 9 Each project must be done in full (with the corresponding cash flows for all four years) or not done at all. Furthermore, there are the following additional considerations: Project 1 cannot be done unless Project 2 is also undertaken, and projects 3 and 4 would compete with each other, so they should not both be chosen. Any available money not spent in a given year is then available to spend in the following year. They want to choose their projects so as to maximize their total expected NPV. a. Write the mathematical model. (15 marks) b. Solve it using Excel solver. (15 marks)