Solve the linear programming model formulated in Problem 25 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?