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Le Monde puzzle [#1707]

July 28, 2017

A geometric Le Monde mathematical puzzle: Given a pizza of diameter 20cm, what is the way to cut it by two perpendicular lines through a point distant 5cm from the centre towards maximising the surface of two opposite slices?  Using the same point as the tip of the four slices, what is the way to […]

Le Monde puzzle [#1016]

July 16, 2017

An even more straightforward Le Monde mathematical puzzle that took a few minutes to code in the train to Cambridge: Breaking {1,…,8} into two sets of four integrals, what is (or are) the division into two groups of equal size such that the sums of the squared terms from each are equal? Same question for […]

Le Monde lacks data scientists!

July 11, 2017

In a paper in Le Monde today, a journalist is quite critical of statistical analyses of voting behaviours regressed on socio-economic patterns. Warning that correlation is not causation and so on and so forth…But the analysis of the votes as presented in the article is itself quite appalling! Just judging from the above graph, where […]

Le Monde puzzle [#1015]

July 10, 2017

A combinatoric Le Monde mathematical puzzle: A game with N questions and N players is such that each question is solved by all players but three, while any pair of players fails to jointly solve the N questions. What is the maximal number N of players? N=6;play=1;besz=1 while ((besz>0)||(play<N)){ gamz=matrix(1,N,N) for (qez in 1:N) gamz[qez,sample(1:N,3)]=0 […]

Le Monde puzzle [#1014]

June 30, 2017

One of those Le Monde puzzles where a computational solution seems out of reach: given 2N batteries out of which N are charged, how many tests of pairs of batteries are necessary to find a working pair? I first tried a brute force recursive resolution checking all (2N-1)N orders of pairs over all (2N)! permutations […]