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Subj:.....The Convent Problem (S628)
          From the book 
            "Mathematical Puzzles of Sam Loyd" 
          Edited by Martin Gardner 
          From: Dover Publications in 1959
 

How many nuns lived in the convent and
what rooms did they occupy?

The problem of the Nuns in the Convent of Mt. Maladetta
appears in almost all collections of puzzles, but it is
childish and the answer too weak to satisfy the expecta-
tions of solvers.

I remember that the answer was very disappointing when I
first saw it many years ago, and I recall the accompany-
ing statement about the problem being of Spanish origin
and founded on an incident which occured many centuries
ago.  Recently I came into possession of some very old
Spanish histories, in one on which I find a brief allusion
to the convent of Mt. Maladetta, situated on the mountain
of that name, the highest peak of the Pyrenees.  Reference
is made to the occupancy of that part of the country by
the French invaders who were finally defeated and driven
out through that famous pass which was the scene of many
contentions for over a century.

The direct allusion to the puzzle, however, occurs in the
passage which says: "Many of the nuns were carried away by
the 'Frank' soldiers, which without doubt gave rise to the
familiar problem of the nuns of the convent of Mt. Maladetta."

As no explanation of the puzzle is vouchsafed, and the popu-
lar version is so susceptible of double solutions, I take the
liberty of presenting it in a form which preserves the spirit
of the problem and at the same time eliminates the many other
answers.

The convent as shown in the picture was a square three-story
structure, with six windows on each side of the upper stories.
It is plain to be seen that there are eight rooms on each of
the upper floors, which agrees with the requirements of the
old story.  As the legend goes, the upper floors were used
for sleeping apartments.  The top floor, having more beds in
each of the rooms, accommodated twice as many occupants as
the second floor.

The Mother Superior, in accordance with an old rule of the
founders, insisted that the occupants must be so divided or
arranged that every room should be occupied; there should be
twice as many on the top floor as on the second, and there
must always be exactly eleven nuns in the six rooms on each
of the four sides of the convent.  The problem pertains only
to the two upper floors, so the ground floor does ont have to
be considered at all.

Well, it happened that after the retreat of the French army
through the Pyrenees pass, nine of the youngest and most
comely nuns were found to have disappeared.  It was always
believed that they had been captured by the soldiers.  Not
to distress the Mother Superior, however, the nuns who
discovered the loss found that it was possible to conceal
the fact by judicious manipulation or change of the occupants
of the rooms.

The nuns managed, therefore, to readjust themselves in such
a way that when the Mother Superior made her nightly rounds,
every room was found to be occupied; eleven nuns on each of
the four sides of the convent; twice as many on the top
floor as on the second, and yet the nine nuns were missing.
How many nuns were there and how were they arranged?

The merit of the puzzle lies in the paradoxical condition of
the problem, which strikes us at first to be absolutely
impossible.  Nevertheless it yields so readily to experimental
puzzle methods, when one knows there is an answer, that our
puzzlists will find it an amusing and instructive lesson.

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