A mechanized stationary container system is proposed for waste collection from a commercial area. The container unloading time is $0.1$ hours per container. There are two containers at each location and the drive time between the two locations is $0.2$ hours. The maximum waste 'pick-up time' is $2.4$ hours per trip.
The 'pick-up time' starts at the instant the truck arrives at the first pick-up location and ends when the last container on the route is emptied. The maximum number of locations which can be covered in a trip by the collection vehicle are ________$\text{(answer in integer)}$.
