Leia, Chewy, Han Solo, and Luke have to cross a bridge. They only have one flashlight, and the bridge can only hold two people at a time. They each take a different length of time to get across the bridge. At any time, a group of two can only move as fast as the group's slowest person. The times that it takes each person to cross the bridge are:
Chewy -- ten minutes
Han Solo -- five minutes
Leia -- two minutes
Luke -- two minutes
How can the four get across the bridge the fastest?