If possible please show how to do it on excel

Industrial Designs has been awarded a contract to design a label for a new wine produced by Lake View Winery. The company estimates that 140 hours will be required to complete the project. The firm's three graphic designers available for assignment to this project are Lisa, a senior designer and team leader; David, a senior designer; and Sarah, a junior designer. Because Lisa has worked on several projects for Lake View Winery, management specified that Lisa must be assigned at least 40% of the total number at hours assigned to the two senior designers. To provide label designing experience for Sarah, the junior designer must be assigned at least 15% of the total project time. However, the number of hours assigned to Sarah must not exceed 25% of the total number of hours assigned to the two senior designers. Due to other project commitments, Lisa has a maximum of 50 hours available to work on this project. Hourly wage rates are $30 for Lisa, $25 for David, and $18 for Sarah. (a) Formulate a linear program that can be used to determine the number of hours each graphic designer should be assigned to the project to minimize total cost (in dollars). (Assure L is the number of hours Lisa is assigned to the project, D is the number of hours David is assigned to the project, and Sis the number of hours Sarah is assigned to the project.) Min St. Minimum Usa Minimum Sarah Maximum Lisa Maximum Sarah Total Time L.D, SO (b) How many hours should be assigned to each graphic designer? Lisa's Hours hours David's Hours hours Sarah's Hours hours What is the total cost (in dollars)? $ $ | (c) Suppose Lisa could be assigned more than 50 hours. What effect would this have on the optimal solution? Explain. The shadow price for this constraints since the constraint is Select. Theretare, additional hours for Lisa Select change the solution ! , . (d) ir Sarah were not required to work a minimum number of hours on this project, would the optimal solution change? Explain. The shadow price for this constraint is since the constraint is ---Select-- V. Therefore, assigning fewer hours to Sarah --Select-- change the solution