During each 6-hour period of the day, the Police Department needs at least the following number of policemen: 12am-6am=12, 6am-12pm=12, 12pm-6pm=4, and 6pm-12am=23. Each policeman has to work two consecutive 12 hours.
If you know the wages of each policeman per hour, what are the decision variables, and how many decision variables and restrictions are in the problem?