Brain Teasers
Brain Teasers Trivia Mentalrobics Games Community
Personal Links
Your Friends
More Community
Newsgroups
Wiki
Teaser Comments
Trivia Comments

User Rankings
Search for User
Add to Google delicious Add to del.icio.us

More ways to get Braingle...
rss

Braingle Time
12:07 pm

Usenet Newsgroups : rec.puzzles Hall of Fame


The rec.puzzles Hall of Fame is a compilation of over 500 of the most popular puzzles that have been posted and discussed in the rec.puzzles newsgroup. In most cases a detailed solution has been provided.

Many of these puzzles also appear in Braingle's own collection.

   
rec.puzzles
Newsgroup
FAQ
Hall of Fame
alt.brain.teasers
Newsgroup
FAQ
Categories : logic : unexpected.p

Swedish civil defense authorities announced that a civil defense drill would
be held one day the following week, but the actual day would be a surprise.
However, we can prove by induction that the drill cannot be held.  Clearly,
they cannot wait until Friday, since everyone will know it will be held that
day.  But if it cannot be held on Friday, then by induction it cannot be held
on Thursday, Wednesday, or indeed on any day.

What is wrong with this proof?


Solution


Users in Chat : Proph 

Online Now: 11 users and 731 guests

Copyright © 1999-2014 | Updates | FAQ | RSS | Widgets | Links | Green | Subscribe | Contact | Privacy | Conditions | Advertise

Custom Search





Sign In A Create a free account