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Logical Puzzles


Hannibal

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Okay, since someone posted some 'brain teasers' and got flamed for it, I thought I might as well try my hand it - this time with a few exercises that I've already done myself. I'd link you to my solutions, but that'd spoil the fun, and besides, they're in Dutch, and the original problems were formulated in dutch as well. They were exercises for my university course in Logic (this is just the first few weeks we've had it, so they're quite doable by just about everyone with some reasoning abilities, imho :) )

 

 

 

 

 

 

 

So, let's get started. All of these puzzles involve a quiz show (or a heroic quest, whatever you like). After winning that quiz show (or slaying some demons), its participant / hero has to pick one of two doors. Either door may hide a princess or a tiger. Maybe both doors have a tiger behind them, maybe both a princess, maybe one of each. You don't know.

 

 

 

 

 

 

 

On both of the doors, there is a hint. These make it clear which door you should pick - at least, if you can figure out the clues.

 

 

 

 

 

 

 


  1.  
     
     
    [*:3jjfubhm]Door 1 says: There's a princess In THIS room. There's a tiger in the other room.
     
     
     
    Door 2 says: There's a princess in one room, and a tiger in the other room.
     
     
     
    One of the statements is true, the other is false. Now in which room is the princess?
     
     
     
    [*:3jjfubhm]Door 1 says: AT LEAST one of the two rooms has a princess in it.
     
     
     
    Door 2 says: There's a tiger in the other room.
     
     
     
    Now, either both statements are false, or both statements are true. Which room has the princess in it?
     
     
     
    [*:3jjfubhm]Door 1 says: At least one of the following is true: 1. There is a tiger in this room. 2. There is a princess in the other room.
     
     
     
    Door 2 says: There's a princess in the other room.
     
     
     
    Again, either both statements must be false, or both statements must be true.

 

 

 

These were the easy ones. For all the following ones, this is the case:

 

 

 

If there is a princess in room 1, then the statement on door 1 is true, otherwise it is false.

 

 

 

If there is a tiger in room 2, then the statement on door 2 is true, otherwise it is false.

 

 

 

Remember that the above MUST be true! Then which room has the princess in it?

 

 

 

 

 

 

 


  1.  
     
     
    [*:3jjfubhm]Door 1 says: There is a princess in both rooms.
     
     
     
    Door 2 says: There is a princess in both rooms.
     
     
     
    [*:3jjfubhm]Door 1 says: There is a princess in AT LEAST 1 room.
     
     
     
    Door 2 says: There is a princess in the other room.
     
     
     
    [*:3jjfubhm]Door 1 says: It doesn't make any difference which room you pick.
     
     
     
    Door 2 says: There's a princess in the other room.
     
     
     
    [*:3jjfubhm]Door 1 says: It DOES make a difference which room you pick.
     
     
     
    Door 2 says: It's better for you to pick the other room.

 

 

 

 

 

 

 

A last one, for the diehards:

 

 

 

There are two hints. They've fallen off their doors. Again, if there is a princess in room 1, whatever once hung on the door of room 1 must be true, if there's a tiger in room 1 then it is false. And once again, whatever hung on the door of room 2 must be true if there's a tiger in room 2, if there's a princess in room 2 then it is false.

 

 

 

One hint reads: There's a tiger in this room.

 

 

 

The other reads: There's a tiger in both rooms.

 

 

 

 

 

 

 

 

 

 

 

Happy puzzling :)

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Sounds like truth tables and such that we did in my pdm class. . .if i wanted to do hw, then i'd do it for a grade :)

 

 

 

 

 

 

 

It's easier if you know how to work with truth tables yeah :). Though I suppose you have a point, that is, if you don't like the subject. I do ;)

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Guest GhostRanger

DONT READ BELOW IF YOU HAVEN'T SOLVED:

 

 

 

 

 

 

 

Are these right...?

 

 

 

 

 

 

 

1

 

 

 

2

 

 

 

1 & 2

 

 

 

 

 

 

 

--

 

 

 

 

 

 

 

2

 

 

 

1

 

 

 

2

 

 

 

 

 

 

 

--

 

 

 

 

 

 

 

2

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GhostRanger: no. For one, you got the first one wrong :P, and the last one too, assuming you meant number 4 of the second list of puzzles. Then you miss one solution (you posted 7 and there's 8 puzzles in total - or didn't you bother solving the last one?). I think the other ones are correct, though.

 

 

 

 

 

 

 

Stevester77: there are multiple puzzles. I posted 8, they're just very similar in a way. The title does read 'puzzles', not 'puzzle'.

 

 

 

 

 

 

 

Mods: don't we have [spoil] [/spoil] tags or something?

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