Please use English as the language of communication at this forum. Otherwise your posts will be tagged as SPAM and will be deleted.Ahoj,
znovu jsem narazil na zajímavý úkol. Dokažte, že je možné zvolit čtyři různá čísla ze sad, která obsahuje šest různých celých čísel, takže [MATH] a_1-a_2 + 2 (a_3-a_4) [/ MATH] je násobkem pěti. Díky.[/MATH]
Is Google right?Hi,
I came across an interesting task again. Prove that it is possible to choose four different numbers from a set that contains six different integers, so that [MATH]a_1 − a_2 + 2 (a_3 − a_4)[/MATH] is a multiple of five. Thanks.
Hi, it is supposed to be true for any set in integers.Is Google right?
This seems incomplete. Do we need to know what the set of six integers is, or is this supposed to be true for any such set?
Thanks. Now we need to know what you have tried (and what you know that might be useful).Hi, it is supposed to be true for any set in integers.
Well, you start wherever you are! That's why I asked for "what you know that might be useful"! Are you taking a course for which this is an exercise? Then tell us what has been taught that this might be intended to use. Is this a contest problem or a practice for an admission exam? Then tell us what prerequisites they expect of you. The more we know of the context, the more likely we can suggest how to begin using your current knowledge, or what to study.I don't know where to start, this is my problem.