Double room: double rooms are assigned to two people; expect one double bed, or two twin beds depending on the hotel. Triple room: as the name might suggest, this room is equipped for three people to stay. The room will have a combination of either three twin beds, one double bed and a twin, or two double beds.
The arrangement gave travelers a less-intimate sleeping arrangement, and “it has a lot more flexibility for hotels,” said Mast, because two twin beds can be separated to accommodate more configurations of travelers than a king bed can.
Why do some hotel rooms have two beds when most people traveling are only one? Simple economics. Cheaper to build larger rooms and accommodate 3–4 people at times. A single person will just normally use one bed, but the spare is there if they rent the room to parties of 2 or more.