USPuzzle Contest: 3 – Crossing Puzzles

Here are three puzzles about crossing barriers under restrictive conditions.  Each puzzle is worth one point.

1. (This one is a classic that I’ve dressed up rather whimsically.  Ignore the silly names if you need to.) You are a Jedi traveling on Naboo.  You have with you an Arcona fugitive, a Trandoshan bounty hunter, and a man-sized bag of salt.  You come to a fast-flowing river with a small skiff moored nearby.  The skiff can carry no more than two beings’ weight at a time, and only you know how to pilot it.  The Arcona has a bounty on his head, and so cannot be left alone with the Trandoshan.  The Arcona also cannot be left alone with the bag of salt for obvious reasons.

How do you get yourself and your party (salt included) across the river without incident?

2. A family of two parents with two teenagers came to a wide river with no bridge. The only way to get to the other side was to ask a fisherman to lend them his boat. However, the boat could not carry more than one adult or two teens at a time.

How does the family get to the other side without leaving the fisherman stranded away from his boat?  How many times does the boat cross the river in the process?

3. Four men are traveling together at night.  They come upon a narrow, treacherous bridge that they must cross.  The bridge can only support two of them at once.  They only have one flashlight among them, and no one is willing to risk crossing the bridge without it (nor are they willing to risk tossing it across the gap – the flashlight must always be carried).  Of the men, Mr. Wan can cross the bridge in 1 minute, Mr. Tsu can do it in 2 minutes, Mr. Fyffe takes 5 minutes, and Mr. Tenn needs 10 minutes to make it across.  If two men walk across the bridge together, they must both travel at the slower one’s pace.

All four men reached the other side in 17 minutes.  How did they do it?

Submit solutions to usp.blogmatters@gmail.com . Fabulous prizes have been confirmed.