Industrial Designs has been awarded a contract to design a label for new wine produced by Lake Winery. The company estimates that 145 hours will be required to complete the project. Three of the firm's graphics designers are available for assignment to this project: Lisa, a senior designer and team leader; David, a senior designer; and Sarah, a junior designer. Because Lisa worked on several projects for Lake View Winery, management has specified that Lisa must be assigned at least 40% of the total number of hours that are assigned to the two senior designers. To provide label-designing experience, Sarah 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 that are 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 $35 for Lisa, $28 for David, and $20 for Sarah. Formulate a linear program that can be used to determine the number of hours each graphic designer should be assigned to the project in order to minimize total cost. What is the total cost?