Consider a simple version of a refinery blending and production problem. This example is more illustrative of a scheduling application (level 5 in Fig. 19.1) that has been used extensively since the 1950 s in the chemical process industries. Figure 19.7 is a schematic diagram of feedstocks and products for the refinery (costs and selling prices are given in parentheses). Table 19.3 lists the information pertaining to the expected yields of the two types of crude oils when processed by the refinery. Note that the product distribution from the refinery is quite different for the two crude oils. Table 19.3 also lists the limitations on the established markets for the various products in terms of the allowed maximum daily production. In addition, processing costs are given. To set up the linear programming problem, formulate an objective function and constraints for the refinery operation. From Fig. 19.7 six variables are involved, namely, the flow rates of the two raw materials and the four products. Solve the LP using the Excel Solver. Figure 19.7 Refinery input and jutput schematic. Find the solution using graphical method and excel solver