Reconsider the Super Grain Corp. case study as presented in Section 3.1. The advertising firm, Giacomi & Jackowitz, now has suggested a fourth promising advertising medium-radio commercials-to promote the company's new breakfast cereal, Crunchy Start. Young children are potentially major consumers of this cereal, but parents of young children (the major potential purchasers) often are too busy to do much reading (so may miss the company's advertisements in magazines and Sunday supplements) or even to watch the Saturday morning programs for children where the company's television commercials are aired.

However, these parents do tend to listen to the radio during the commute to and from work. Therefore, to better reach these parents, Giacomi & Jackowitz suggests giving consideration to running commercials for Crunchy Start on nationally syndicated radio programs that appeal to young adults during typical commuting hours.

Giacomi & Jackowitz estimates that the cost of developing each new radio commercial would be $50,000, and that the expected number of exposures per commercial would be 900,000. The firm has determined that 10 spots are available for different radio commercials, and each one would cost $200,000 for a normal run.

a. Formulate and solve a spreadsheet model for the revised advertising-mix problem that includes this fourth advertising medium. Identify the data cells, the changing cells, and the objective cell. Also show the Excel equation for each output cell expressed as a SUMPRODUCT function.

b. Indicate why this spreadsheet model is a linear programming model.

c. Express this model in algebraic form?