Brain-Twisters (September 1996)



The puzzles in this page will generally be examples of the categories I
enjoy most - those involving geometry, topology, probability, and truth
paradoxes. Presenting them will often involve the use of tables and figures.
The page should still be readable with text-based browsers such as Lynx,
provided the reader has some way of downloading and viewing the gif figures.



Puzzle #1



Brought back by popular demand, this is yet another set of the classic "Lady
or the Tiger" puzzles. The rules this time are a little different. If a lady
is in Room I, then the sign on the door is true, but if a tiger is in it,
the sign is false. In Room II, the situation is the opposite: a lady in the
room means the sign on the door is false, and a tiger in the room means the
sign is true. Again, it is possible that both rooms contain ladies or both
rooms contain tigers, or that one room contains a lady and the other a
tiger. The signs on the doors of the rooms are as follows:





                       I                          II

           BOTH ROOMS CONTAIN LADIES  BOTH ROOMS CONTAIN LADIES



Which door should you open (assuming, of course, that you prefer the lady to
the tiger)?

Solution.

                                


Puzzle #2





This time the signs read as follows:



                       I                           II

           AT LEAST ONE ROOM CONTAINS  THE OTHER ROOM CONTAINS A
                     A LADY                      LADY



What should you do?



Solution.

                             


Puzzle #3



The signs now read:



                         I                           II



            IT MAKES NO DIFFERENCE WHICH   THERE IS A LADY IN THE
                   ROOM YOU PICK                OTHER ROOM





What should you do?



Solution.

                                


Puzzle #4



Here are the signs:



                        I                          II

            IT DOES MAKE A DIFFERENCE      YOU ARE BETTER OFF
               WHICH ROOM YOU PICK      CHOOSING THE OTHER ROOM

What should you do?

Solution.

                                


Puzzle #5

This time the signs are not attached to the doors:

         THIS ROOM CONTAINS A TIGER  BOTH ROOMS CONTAIN TIGERS

Can you still figure out the solution?

Solution.