need help with #22

U c. Identify the sensitivity ranges for the profit of a sausage Biscuit available. Explain these sensitivity ranges. 21. Rucklehouse Public Relations has been contracted to do a survey following an election primary in New Hampshire. The firm must assign interviewers to conduct the survey by telephone or in person. One person can conduct 80 telephone interviews or 40 personal interviews in a single day. The following criteria have been established by the firm to ensure a representative survey: At least 3.000 interviews must be conducted. At least 1,000 interviews must be by telephone. . At least 800 interviews must be personal. An interviewer conducts only one type of interview each day. The cost is $50 per day for a telephone interviewer and $70 per day for a personal interviewer. The firm wants to know the minimum number of interviewers to hire to minimize the total cost of the survey. Formulate a linear programming model for this problem. 22. Solve the linear programming model formulated in Problem 21 for Rucklehouse Public Relations graphically. a. Determine the sensitivity ranges for the daily cost of a telephone interviewer and the number of personal interviews required. b. Does the firm conduct any more telephone and personal interviews than are required, and if so, how many more? c. What would be the effect on the optimal solution if the firm was required by the client to increase the number of personal interviews conducted from 800 to a total of 1,200? 23. Solve the linear programming model formulated in Problem 21 for Rucklehouse Public Relations by using the computer. a. If the firm could reduce the minimum interview requirement for either telephone or personal which should the firm select? How much would a reduction of one interview in nt you selected reduce total cost? Solve the model again, using the computer, ion of this one interview in the constraint requirement to verify your