Solve the practical optimization problem and use one of the techniques from this section t...

Solve the practical optimization problem and use one of the techniques from this section to verify that you have actually found the desired absolute extremum.

BROADCASTING An all-news radio station has made a survey of the listening habits of local residents between the hours of 5:00 p.m. and midnight. The survey indicates that the percentage of the local adult population that is tuned in to the station x hours after 5:00 p.m. is

a. At what time between 5:00 p.m. and midnight are the most people listening to the station? What percentage of the population is listening at this time?

b. At what time between 5:00 p.m. and midnight are the fewest people listening? What percentage of the population is listening at this time?