Four people come to a river in the night. There is a narrow bridge, but it can only hold two people at a time. Because it is night, a torch has to be used when crossing the bridge. Person A can cross the bridge in 1 minute, B in 2 minutes, C in 5 minutes, and D in 8 minutes. When two people cross the bridge together, they must move at the slower person's pace. The group only has one torch between them. How can all four people get to the far side of the bridge in 15 minutes or less?
