Question # 3. (5 Marks) A Media & Public Relations company has been contracted to do a survey following the launching of a new product at Jubail. The rm 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 rm to ensure a representative survey: 0 At least 3,000 interviews must be conducted. 0 At least 1,000 interviews must be by telephone. a 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 rm wants to know the minimum number of interviewers to hire in order to minimize the total cost of the survey. a. [1 Mark] Formulate a linear programming model for this problem. b. [1 Mark] Solve the problem using software and show the output. c. [0.5 Mark] Determine the sensitivity ranges for the daily cost of a telephone interviewer and the number of personal interviews required. (1. [0.5 Mark] Does the rm conduct any more telephone and personal interviews than are required, and if so, how many more? C. [0.5 Mark] What would be the effect on the optimal solution if the rm was required by the client to increase the number of personal interviews conducted from 800 to a total of 1,200? f. [1 Mark] If the rm could reduce the minimum interview requirement for either telephone or personal interviews, which should the rm select? How much would a reduction of one interview in the requirement you selected reduce total cost? g. [0.5 Mark] Identify the sensitivity ranges for the cost of a personal interview and the number of total interviews required