# What are your favorite logic puzzles?

Asked by phoenyx (7385) June 14th, 2009

Please give both your puzzle and its solution. Please use ROT13 to encrypt your solution. There are plenty of ROT13 conversion websites that will do it for you. I used this one.

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Puzzle:
Why did the chicken cross the road?

Solution:
gb trg gb gur bgure fvqr

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Also, if you have questions about a puzzle for someone, an alternate solution, etc. please ROT13 as well so that you don’t spoil it for others.

Observing members: 0 Composing members: 0

Puzzle:
There are three boxes of fruit. One has only oranges, one has only apples, and one has both apples and oranges in it. Each box has a label. One is labeled “Apples”, one is labeled “Oranges”, and one is labeled “Apples and Oranges”. You know that every label is wrong. If you are allowed to take only one fruit from one box (without peeking inside), which box do you choose and how do you use that information to move the correct label to the correct box?

Solution:
Lbh xabj gung nyy bs gur obkrf ner ynoryrq vapbeerpgyl, fb lbh gnxr n sehvg sebz gur obk ynoryrq “nccyrf naq benatrf”. Vs lbh trg na nccyr lbh xabj gung gur obk unf bayl nccyrf. Abj lbh nyfb xabj gung gur obk ynoryrq “benatrf” pna’g pbagnva bayl benatrf, ohg zhfg or “nccyrf naq benatrf”. Gur ynfg obk unf bayl benatrf. Gur fnzr ybtvp nccyvrf vs lbh chyy bhg na benatr.

phoenyx (7385)

Puzzle:
A family has 5 children. Half of them are boys. How?

Solution:
Nyy gur puvyqera ner oblf.

Bri_L (12206)

The game of Mastermind.

Jeruba (52943)

Ben once gave me a diabolical math one about prisoners and lightswitches, and it took me and a friend a few days to solve it. Such a good one though.

andrew (16456)

@andrew – Post IT! Post it! I feel the need to be mentally tortured!

Bri_L (12206)

PUZZLE
Which came first, the chicken or the egg?
Gur ebbfgre.

filmfann (50216)

Question…

5 5 5 5 = 56 how?

55 5/5

boffin (9981)

Puzzle:
There is a monastery on an island. Each of the monks of the monastery has taken solemn vows that they would rather die than break:

1. A monk may not look at his own image (including reflections) or any representation thereof.

2. A monk may not describe (or indirectly reveal) in any way any part of of any person’s appearance to any other person.

3. A monk may speak only one word in his lifetime.

Each monk has grown tired of his life at the monastery and desires to leave the island and see the world. Every night a ship comes to the island to bring supplies to the monastery and to trade for the goods produced by the monks. The captain of the ship knows the vows the monks have made and of their desire to leave. He has made them a rather devious offer: any monk who can say (verbally) what color his own eyes are to the captain can leave the island. Unfortunately, although every monk knows the eye colors of all of the other monks, each does not know his own because of the vows taken. If there is a way a monk can be certain of his eye color he would absolutely tell the captain and leave the island. If the monk cannot be certain he will stay on the island because he dare not be wrong, waste his one utterance, and be stuck on the island forever.

One day a hermit (who happens to have purple eyes and has taken a vow of absolute honesty) comes out of a cave while the monks are all together. He says to them “I see a monk with blue eyes” and leaves back into his cave.

There are exactly 100 people on the island. There is 1 hermit and 99 monks: 33 with green eyes, 33 with blue eyes, and 33 with brown eyes. Who leaves the island and on what night after the hermit’s visit?

Solution:
Ba gur guvegl-guveq avtug nyy guvegl-guerr bs gur zbaxf jvgu oyhr rlrf yrnir gur vfynaq.

Gur rnfvrfg jnl gb frr jul guvf vf vf gb pbafvqre gur fbyhgvba vs gurer jnf bar zbax jvgu oyhr rlrf. Jura gur urezvg fnlf gung ur frrf n zbax jvgu oyhr rlrf gur zbax jvgu oyhr rlrf pna frr gung abar bs uvf sryybj zbaxf unir oyhr rlrf naq pna gurersber pbapyhqr gung ur vf gur zbax jvgu oyhr rlrf. Gur svefg avtug gur bar zbax jvgu oyhr rlrf gryyf gur pncgnva “oyhr” naq yrnirf.

Abj fhccbfr gung gurer ner gjb zbaxf jub unir oyhr rlrf. Gur svefg zbax ybbxf ng gur frpbaq zbax naq nffhzrf gung gur svefg zbax jvyy yrnir orpnhfr ur vf gur bayl zbax ur pna frr jub unf oyhr rlrf. Gur frpbaq zbax ybbxf ng gur svefg zbax naq nyfb nffhzrf gung ur jvyy yrnir orpnhfr ur vf gur bayl zbax ur pna frr jub unf oyhr rlrf. Jura obgu gur svefg zbax naq gur frpbaq zbax fgnl, rnpu zbax ernyvmrf gung ur uvzfrys zhfg nyfb unir oyhr rlrf. Fb, ba gur frpbaq avtug gur gjb zbaxf jvgu oyhr rlrf yrnir.

Fb, jvgu guerr zbaxf vg vf gur guveq avtug. Jvgu sbhe zbaxf vg vf gur sbhegu avtug. Naq fb ba.

phoenyx (7385)

or