40 A snowmobile manufacturer produces three models, the XJ6, the XJ7, and the XJ8. In any given productionplanning week, the company has 40 hours available in its final testing bay. Each XJ6 requires 1 hour of testing, each XJ7 requires 1.5 hours, and each XJ8 takes 1.6 hours. The revenue (in $thousands) per unit of each model is defined as 1+4 - +0.1X12 for XJ6, 1+5 - +0.2X22 for XJ7, and 1+6 - +0.2X32 for XJ8, where X1 , X2 , and X3 are the numbers of XJ6, XJ7, and XJ8 models made, respectively. Formulate this problem to maximize revenue and solve it by using Excel. Use several different starting values for the decision variables to try to identify a global optimal solution.