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Le Monde puzzle [#1029]

November 22, 2017

A convoluted counting Le Monde mathematical puzzle: A film theatre has a waiting room and several projection rooms. With four films on display. A first set of 600 spectators enters the waiting room and vote for their favourite film. The most popular film is projected to the spectators who voted for it and the remaining […]

Le Monde puzzle [#1028]

November 16, 2017

Back to standard Le Monde mathematical puzzles (no further competition!), with this arithmetic one: While n! cannot be a squared integer for n>1, does there exist 1<n<28 such that 28(n!) is a square integer? Does there exist 1<n,m<28 such that 28(n!)(m!) is a square integer? And what is the largest group of distinct integers between […]

Le Monde [last] puzzle [#1026]

November 2, 2017

The last and final Le Monde puzzle is a bit of a disappointment, to wit: A 4×4 table is filled with positive and different integers. A 3×3 table is then deduced by adding four adjacent [i.e. sharing a common corner] entries of the original table. Similarly with a 2×2 table, summing up to a unique […]

Le Monde puzzle [poll]

November 1, 2017

As the 25 Le Monde mathematical puzzles have now been delivered (plus the extraneous #1021), the journal is asking the players for their favourites, in order to separate ex-aequos. For readers who followed the entire sequence since puzzle #1001, what are your favourite four puzzles? (No more than four votes!)

Le Monde puzzle [open problem]

October 23, 2017

What should have been the last puzzle in Le Monde competition turned out to be an anticlimactic fizzle on how many yes-no questions are needed to identify an integer between 1 and 1025=2¹⁰+1 and an extension to replies possibly being lies… What is much more exciting is that voting puzzle #1021 got cancelled because the […]