Introduction to Management Science 12th Edition by Bernard Taylor

Exercise 38

Solve the linear programming model formulated in Problem for Rucklehouse Public Relations by using the computer.
a. If the firm could reduce the minimum interview requirement for either telephone or personal interviews, which should the firm select How much would a reduction of one interview in the requirement you selected reduce total cost Solve the model again, using the computer, with the reduction of this one interview in the constraint requirement to verify your answer.
b. Identify the sensitivity ranges for the cost of a personal interview and the number of total interviews required.
Problem
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 in order to minimize the total cost of the survey.
Formulate a linear programming model for this problem.