Four friends named (for a reason that will be made clear shortly) One, Two, Five, and Ten have gotten lost in the woods and are trying to find their way out, hiking in the dark with their only flashlight. They come to an old rope bridge across a canyon. They determine that the bridge would be too dangerous to cross without the flashlight, and that it could support at most two of the hikers at a time. They will send two people over then one will return with the flashlight, and repeat until all are across.
Each hiker's name tells you how many minutes it takes the hiker to cross the bridge. When two are crossing together, they go at the rate of the slower hiker.
How quickly can all four get across the canyon?