:9-28 The Gleaming Company has just developed a new dishwashing liquid and is preparing for a national television promotional campaign. The firm has decided to schedule a series of 1-minute commer- cials during the peak homemaker audience viewing hours of 1 P.M. to 5 P.M. To reach the widest possible audience, Gleaming wants to schedule one commer- cial on each of four networks and to have one com- mercial appear during each of the four 1-hour time blocks. The exposure ratings for each hour, which represent the number of viewers per $1,000 spent, are presented in the following table. Which network should be scheduled each hour to provide the maxi- mum audience exposure? NETWORK VIEWING HOURS A B C INDEPENDENT 1-2 P.M. 27.1 18.1 11.3 2-3 P.M. 18.9 15.5 17.1 9.5 10.6 3-4 P.M. 19.2 18.5 9.9 7.7 4-5 P.M. 11.5 21.4 16.8 12.8