(January 29, 2010 at 3:28 am)TruthWorthy Wrote: where's the problem?Erm:
easy! person 1 accompanies on every trip
and saves a minute
A & B go across - 2 minutes.
A goes back with torch - 1 minute.
A & C go across - 5 minutes.
A goes back with torch - 1 minute.
A & D go across - 10 minutes.
2 + 1 + 5 + 1 + 10 = 19.
How did you mean? How did you "save a minute"?