Assume a large number of cardboard sheets with 23 inch width is available. From these 23" sheets, we need to cut sheets with width 6", 7", and 8" in only one direction. The demand for sheets with width 6", 7", and 8" is 3000, 1000, and 2000, respectively. We would like to minimize the wastage, while satisfying the demand.

Formulate the optimization model for question 2: provide a list of decision variables (1 points), objective function (1 points), and constraints (3 points), and identify the optimal solution by Excel Solver (5 points).