Semaine Européenne
Concours de mathématiques

La réponse officielle au problème français
The answer from Lancaster

Solution:  L'explorateur part avec deux porteurs: P1 et P2.
A bout du premier jour :
Il reste trois rations à chaque personne.
P1 rentre en emportant un ration pour le retour. Il donne une ration à l'explorateur et une à P2 : ce qui leur fait quatre rations chacun.
A bout du deuxième jour :
Il reste trois rations à chaque personne.
P2 rentre en emportant deux rations pour le retour. Il donne la troisième ration à l'explorateur, ce qui lui fait quatre rations.
Comme il ne reste que quatre jours de marche et qu'il lui reste quatre rations, l'explorateur traversera le désert.

Answer:The explorer sets off  on his trip with two bearers named B1 and B2.
By the end of the first day, there are three rations left for each of them.
B1 comes back, bringing one ration for the  return trip. He gives one ration to the explorer and another one to B2. As a result, each of them has got 4 rations.
By the end of the second day, there are three rations left for each. B2 comes back, bringing two rations for the trip back. He gives the third  one  to the explorer which makes 4 rations altogether.
As there are only four days' walking left and as well as 4 rations , the explorer   will walk across the desert.

The answer from Lancaster :

2 bearers are needed.
One retums after one day, after giving one of his rations to another bearer, and the other to TRAVELS EVERYWHERE.
Now both TE and the second bearer have four rations each.
After the second day, the second bearer retums, after giving one to TE and using the other two to get back.
Therefore, TE has four rations for the remaining four days.
                                                            Thom Yorke, Tom Nelson, Anna Sliwa