Find the greatest positive integer $x$ such that $23^{6+x}$ divides $2000!$
Problem
Source:
Tags: floor function, number theory proposed, number theory
30.10.2010 20:04
WakeUp wrote: Find the greatest positive integer $x$ such that $23^{6+x}$ divides $2000!$ $v_{23}(2000!)=\sum_{k=1}^{+\infty}\left\lfloor\frac{2000}{23^k}\right\rfloor$ $=\left\lfloor\frac{2000}{23}\right\rfloor$ $+\left\lfloor\frac{2000}{23^2}\right\rfloor$ $=86+3=89$ So $\boxed{x=83}$
19.01.2017 07:32
I don't understand what the point of $23^{6+x}$. Why not just $23^x$ or something? Is there a typo?
16.08.2021 17:52
Hmmm why exactly is this in an Olympiad Shortlist
16.08.2021 18:02
16.08.2021 18:06
judgefan99 wrote: OlympusHero wrote: Hmmm why exactly is this in an Olympiad Shortlist
Hmmm why exactly are you flexing Are you kidding me? I made a comment. Anyone experienced with Olympiad would agree this is too easy to be in an Olympiad Shortlist. Just look at even the A1, G1, N1, C1 of the Shortlist from recent Olympiad and compare.
16.08.2021 18:08
it's the junior balkian mathmatical olympiad so it's not supposed to be terribly difficult
16.08.2021 18:11
Yes, I know, but if you compare this to the recent problems from the Junior Balkan Math Olympiad, the difference is large!
16.08.2021 19:47
Probably why it got shortlisted.
09.09.2021 14:05
The amount of multiples of 23 that are in the product $2000!$ are $$\left\lfloor\frac{2000}{23}\right\rfloor+\left\lfloor\frac{2000}{23^2}\right\rfloor=86+3=89$$Therefore, $6+x=89$, so $x=\boxed{83}$.
06.05.2023 05:56
$e_{23}(2000!)=\left\lfloor\frac{2000}{23}\right\rfloor$ $+\left\lfloor\frac{2000}{23^2}\right\rfloor$ $=86+3=89$ $x=83$ seemed way too easy for a shortlist... even relative to oldest jbmo p1s
22.07.2023 21:27
We use Legendra's so we have 2000/23 (floor)+2000/529 (floor)=$86+3=89$, so $x=83$
23.07.2023 08:02
WakeUp wrote: Find the greatest positive integer $x$ such that $23^{6+x}$ divides $2000!$ use legandra done.