On paper, formulate each problem as a (mixed-)integer linear programming model in proper notation. Define all decision variables. For their implementation and solution in Excel, create each spreadsheet model with intuitive labels for its cells, columns, rows, constraints, variables and objective.

Please include all steps to solve the problem on Excel.

9. Make Versus Buy for Textiles. The Calhoun Textile Mill is in the process of deciding on a production schedule. It wishes to know how to weave the various fabrics it will produce during the coming quarter. The sales department has confirmed orders for each of the 15 fabrics produced by Calhoun. These demands are given in the following table. Also given in this table is the variable cost for each fabric. The mill operates continuously during the quarter: 13 weeks, 7 days a week, and 24 hours a day. There are two types of looms: dobby and regular. Dobby looms can be used to make all fabrics and are the only looms that can weave certain fabrics, such as plaids. The rate of production for each fabric on each type of loom is also given in the table. Note that if the production rate is zero, the fabric cannot be woven on that type of loom. Also, if a fabric can be woven on each type of loom, then the production rates are equal. Calhoun has 90 regular looms and 15 dobby looms. For this problem, assume that the time requirement to change over a loom from one fabric to another is negligible. In addition to producing the fabric using dobby and regular looms, Calhoun has the option to buy some or all of each fabric on the market. The market cost per yard for each fabric is given in the table. Management would like to know how to allocate the looms to the fabrics and which fabrics to buy on the market so as to minimize the cost of meeting demand