Friday, February 25, 2011

wine puzzle

A little brain teaser to celebrate the VA Wine Expo (reminder: the latest 2011 VA Winery Guide map is out).

All those pourings made me remember this classic (way back from the 16th century) puzzle (part of the so-called decanting puzzles)
Imagine we have three jugs of 8, 5 and 3 liters. The biggest jug is entirely filled with wine, and the other two are empty. We want to divide the wine into 2 equal parts. The jugs are not calibrated, so that all we can do is pour wine from one jug to another until the first jug is entirely empty or the second jug is completely full. We also assume that the decantings are done accurately and that no wine is spilled. HOW ?

Interesting side note: A two jug variant of this decanting puzzle was used in Die Hard: With a Vengeance. John McClane and Zeus Carver (Bruce Willis and Samuel L. Jackson) have to solve the puzzle with two jugs and water from a fountain to prevent a bomb from exploding - 4 gallons of water using only 5-gallon and 3-gallon jugs.

Hint: In symbolic terms if our starting point is 8 0 0 (8 liter full, 5 liter empty, 3 liter empty), we need to get to 4 4 0. Multiple solutions exist.

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