A family of 5 (a, b, c, d, e) want to cross a river by boat.  The boat is capable of holding at most 2 people at a time.  Travel time for person a takes 1 minute; person b takes 3 minutes; person c takes 6 minutes; person d takes 8 minutes; and person e takes 12 minutes.  If two people row the boat at the same time, the boat goes at the slower person's pace.  To win the game, a player must find a series of 7 crossings that gets all five people across the river in no more than 29 minutes.