A climber leaves at sunrise and ascends the narrow trail that leads to the summit of a tall Appalachian peak. He varies his speed and takes several rests along the way, finally reaching the peak. The next morning at sunrise he begins to walk down the mountain along the same trail. Part of the way down, he reaches a spot at the exact same time that he was there the previous day on his way up. When he tells his wife, she says “Of course, that was bound to happen.” She offers a simple proof. What was it?
Just a little riddle