The Grey Labyrinth is a collection of puzzles, riddles, mind games, paradoxes and other intellectually challenging diversions. Related topics: puzzle games, logic puzzles, lateral thinking puzzles, philosophy, mind benders, brain teasers, word problems, conundrums, 3d puzzles, spatial reasoning, intelligence tests, mathematical diversions, paradoxes, physics problems, reasoning, math, science.

Ghost Post · Icarian Member

Just thought I'd offer another solution. I believe this way is actually a few steps shorter.

Fill the five-cup vessel to the top. Pour it into and fill the three-cup vessel, leaving two cups in the five-cup vessel. Pour the three-cup vessel back into the bowl. Pour the remaing two cups from the five-cup vessel into the three-cup vessel. Fill the five-cup vessel to the top and pour all that will fit, which is one cup, into the three-cup vessel, leaving four cups in the five-cup vessel.

Murray · Daedalian Member

Yup, this works, and does seem to take fewer steps (six steps versus eight steps, by my count).

Ghost Post · Icarian Member

Here is the interesting solution that I have seen, though I forgot where:

Fill the five-cup container. Use this to pour out three cups into the other.
You now have two cups in the five-cup container. Drink it! Do this again, and you will have drunk exactly four cups. Nothing in the problem stated that the four cups had to be consumed simultaneously!

Andy · Daedalian Member

The two-cups-at-a-time solution was posted in the old GL Discussion Forum - you may have seen it there, or somewhere else. This kind of ambiguity in the puzzle statements seems to inspire a lot of creativity - that's one of the things I like about this forum.