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Contests & Programs AMC and other contests, summer programs, etc.
AMC and other contests, summer programs, etc.
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Contests & Programs AMC and other contests, summer programs, etc.
AMC and other contests, summer programs, etc.
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thank you
Piwbo   1
N an hour ago by CHESSR1DER
Let $p_n$ be the n-th prime number in increasing order for $n\geq 1$. Prove that there exists a sequence of distinct prime numbers $q_n$ satisfying $q_1+q_2+...+q_n=p_n$ for all $n\geq 1 $
1 reply
Piwbo
Yesterday at 11:22 AM
CHESSR1DER
an hour ago
Difficult lattice point coloring problem
CBMaster   0
an hour ago
Source: Own
Is it possible to color all lattice points in plane into 3 colors such that

1. every line passing through lattice points and parallel to x axis has these three colors infinitely many(that is, every color appears infinitely many times in those lines).

2. every line passing through lattice points and not parallel to x axis cannot have three different color lattice points on it.
0 replies
CBMaster
an hour ago
0 replies
Stop Projecting your insecurities
naman12   52
N an hour ago by ihategeo_1969
Source: 2022 USA TST #2
Let $ABC$ be an acute triangle. Let $M$ be the midpoint of side $BC$, and let $E$ and $F$ be the feet of the altitudes from $B$ and $C$, respectively. Suppose that the common external tangents to the circumcircles of triangles $BME$ and $CMF$ intersect at a point $K$, and that $K$ lies on the circumcircle of $ABC$. Prove that line $AK$ is perpendicular to line $BC$.

Kevin Cong
52 replies
naman12
Dec 12, 2022
ihategeo_1969
an hour ago
Digit sum
Disjeje   3
N an hour ago by jasperE3
Let’s say S(n) is digit sum of n does n exists thatS(n)>S(n^2)?
3 replies
Disjeje
5 hours ago
jasperE3
an hour ago
R+ Functional Equation
Mathdreams   3
N an hour ago by jasperE3
Source: Nepal TST 2025, Problem 3
Find all functions $f : \mathbb{R}^+ \rightarrow \mathbb{R}^+$ such that \[f(f(x)) + xf(xy) = x + f(y)\]for all positive real numbers $x$ and $y$.

(Andrew Brahms, USA)
3 replies
Mathdreams
5 hours ago
jasperE3
an hour ago
TST Junior Romania 2025
ant_   0
an hour ago
Source: ssmr
Consider the isosceles triangle $ABC$, with $\angle BAC > 90^\circ$, and the circle $\omega$ with center $A$ and radius $AC$. Denote by $M$ the midpoint of side $AC$. The line $BM$ intersects the circle $\omega$ for the second time in $D$. Let $E$ be a point on the circle $\omega$ such that $BE \perp AC$ and $DE \cap AC = {N}$. Show that $AN = 2AB$.
0 replies
ant_
an hour ago
0 replies
Functional equation
Pmshw   16
N an hour ago by jasperE3
Source: Iran 2nd round 2022 P2
Find all functions $f:\mathbb{R}\rightarrow \mathbb{R}$ such that for any real value of $x,y$ we have:
$$f(xf(y)+f(x)+y)=xy+f(x)+f(y)$$
16 replies
Pmshw
May 8, 2022
jasperE3
an hour ago
Line passes through the fix point
moony_   1
N 2 hours ago by GioOrnikapa
Source: idk
Let $ABC$ be a triangle. $P$ and $Q$ are points, such that $PA = PB$, $QA$ = $QC$ and $\angle{PBC} =\angle{QCB}$ ($P$ - inside $\triangle{ABC}$ and $Q$ - oitside). Proove that line $PQ$ passes through the fix point.
1 reply
moony_
5 hours ago
GioOrnikapa
2 hours ago
Subsets of points lying in disks
oVlad   4
N 2 hours ago by Andyexists
Source: Romania TST 2023 Day 2 P4
Fix a positive integer $n.{}$ Consider an $n{}$-point set $S{}$ in the plane. An eligible set is a non-empty set of the form $S\cap D,{}$ where $D$ is a closed disk in the plane. In terms of $n,$ determine the smallest possible number of eligible subsets $S{}$ may contain.

Proposed by Cristi Săvescu
4 replies
oVlad
Apr 7, 2024
Andyexists
2 hours ago
hard ...
REGNA   3
N 2 hours ago by KenWuMath
find function $f:\mathbb{R^+}\rightarrow \mathbb{R^+}$ such that :
$f()\frac{f(x)}{y}=yf(y)f(f(x)) \;\;\;\;\;(x,y> 0)$
3 replies
REGNA
Oct 21, 2022
KenWuMath
2 hours ago
ELMO 2014 [SL, Problems, Solutions, and Results]
v_Enhance   103
N Jul 31, 2014 by mentalgenius
Source: Mock Olympiad
16th Ego Loss May Occur
June 15, 2013 and June 21, 2013
Lincoln, Nebraska

A total of 411 points were given out to 27 contestants (compared to 410 points over 29 last year), for an average score of 15.22 (compared to 14.14 last year). The problems and solutions for the ELMO, as well as the ELSMO, have been attached to this post. The shortlist will be coming out sometime soon.

This year, the gold medalists were LIU2 Michael Ma, WWP3 Calvin Lee, and WWP4 Ashwin Sah, each with 29 points. The winning team was We Won't Phail WWP, with leaders Ryan Alweiss, Brice Huang, Kevin Li, and Michael Seaman. The complete MOP results are at the ELMO website, http://web.mit.edu/~evanchen/www/elmo/.

The top scores on AoPS were:
:winner_first: Avengers, 28 points
:winner_second: mssmath, 21 points
:winner_third: AndrewKwon97, 16 points
In addition, ABCDE, msinghal, and explogabloger each earned 14 points.

The highest D1 score was 7, achieved by Avengers, mssmath, and msinghal. The highest D2 score was 21, achieved by Avengers.

Thank you to everyone who participated!

IMAGE

---

Good morning from ARML Las Vegas! Due to popular request, like last year we will be letting AoPS-ers compete unofficially alongside the MOP attendees at the 16th ELMO.

For those of you that don't already know, the ELMO is an IMO-style exam prepared by returning MOPpers for the new MOPpers. You can see links for the ELMO in 2009, 2010, 2011, 2012 and 2013. The ELMO and its shortlist are also available in the USA contest section. The name of the acronym changes every year.

The proceedings are otherwise similar to last year.
[list][*]Sign-up in thread. This sign-up is non-binding and non-mandatory, it's just so I have a rough idea of how many people are submitting.
[*]You may participate in either Day 1, Day 2, or both. I will post the top scores from each day as well as the top total scores.
[*]Both days are due 72 hours after Day 2 is posted.
[*]Each day should be taken under the same conditions as the USAMO, with one exception: you can type up your solutions in LaTeX if you prefer.
[*]Submit your solutions as a PDF, either scanned or LaTeX-ed, to mockjmo.solutions@gmail.com. Do not send solutions by PM.
[*]Please do not discuss the problems with others who have not taken the contest until the solutions are posted here. If you want to chat about the problems with people who have already seen the test that is perfectly okay, but please do not spoil the problems for others.[/list]

We look forward to your participation!
103 replies
v_Enhance
May 30, 2014
mentalgenius
Jul 31, 2014
ELMO 2014 [SL, Problems, Solutions, and Results]
G H J
G H BBookmark kLocked kLocked NReply
Source: Mock Olympiad
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v_Enhance
6872 posts
#1 • 10 Y
Y by ahaanomegas, dantx5, droid347, ABCDE, Amir Hossein, TheMaskedMagician, MSTang, mathleticguyyy, HamstPan38825, Adventure10
16th Ego Loss May Occur
June 15, 2013 and June 21, 2013
Lincoln, Nebraska


A total of 411 points were given out to 27 contestants (compared to 410 points over 29 last year), for an average score of 15.22 (compared to 14.14 last year). The problems and solutions for the ELMO, as well as the ELSMO, have been attached to this post. The shortlist will be coming out sometime soon.

This year, the gold medalists were LIU2 Michael Ma, WWP3 Calvin Lee, and WWP4 Ashwin Sah, each with 29 points. The winning team was We Won't Phail WWP, with leaders Ryan Alweiss, Brice Huang, Kevin Li, and Michael Seaman. The complete MOP results are at the ELMO website, http://web.mit.edu/~evanchen/www/elmo/.

The top scores on AoPS were:
:winner_first: Avengers, 28 points
:winner_second: mssmath, 21 points
:winner_third: AndrewKwon97, 16 points
In addition, ABCDE, msinghal, and explogabloger each earned 14 points.

The highest D1 score was 7, achieved by Avengers, mssmath, and msinghal. The highest D2 score was 21, achieved by Avengers.

Thank you to everyone who participated!

//cdn.artofproblemsolving.com/images/e79c746dae42ba17721c94565a1da582149054cd.png

---

Good morning from ARML Las Vegas! Due to popular request, like last year we will be letting AoPS-ers compete unofficially alongside the MOP attendees at the 16th ELMO.

For those of you that don't already know, the ELMO is an IMO-style exam prepared by returning MOPpers for the new MOPpers. You can see links for the ELMO in 2009, 2010, 2011, 2012 and 2013. The ELMO and its shortlist are also available in the USA contest section. The name of the acronym changes every year.

The proceedings are otherwise similar to last year.
  • Sign-up in thread. This sign-up is non-binding and non-mandatory, it's just so I have a rough idea of how many people are submitting.
  • You may participate in either Day 1, Day 2, or both. I will post the top scores from each day as well as the top total scores.
  • Both days are due 72 hours after Day 2 is posted.
  • Each day should be taken under the same conditions as the USAMO, with one exception: you can type up your solutions in LaTeX if you prefer.
  • Submit your solutions as a PDF, either scanned or LaTeX-ed, to mockjmo.solutions@gmail.com. Do not send solutions by PM.
  • Please do not discuss the problems with others who have not taken the contest until the solutions are posted here. If you want to chat about the problems with people who have already seen the test that is perfectly okay, but please do not spoil the problems for others.

We look forward to your participation!
Attachments:
ELMO_2014_D1_D2_Final.pdf (350kb)
ELMO_2014_Solutions.pdf (222kb)
ELSMO_2014.pdf (620kb)
shortlist.pdf (420kb)
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Konigsberg
2205 posts
#2 • 2 Y
Y by Adventure10, Mango247
Signups:
1. Konigsberg

Would we be allowed to form teams and have our results posted on the websites?
Z K Y
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mathman98
581 posts
#3 • 2 Y
Y by Adventure10, Mango247
1. Konigsberg
2. mathman98
Z K Y
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ABCDE
1963 posts
#4 • 1 Y
Y by Adventure10
1. Konigsberg
2. mathman98
3. ABCDE
Z K Y
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AndrewKwon97
130 posts
#5 • 2 Y
Y by Adventure10, Mango247
Signups
Z K Y
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exmath89
2572 posts
#6 • 2 Y
Y by Adventure10, Mango247
Signups
Z K Y
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msinghal
725 posts
#7 • 2 Y
Y by Adventure10, Mango247
Signups
Z K Y
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mymathboy
163 posts
#8 • 2 Y
Y by Adventure10, Mango247
Signups
Z K Y
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SMOJ
2663 posts
#9 • 1 Y
Y by Adventure10
Signups

I will just try to get something better than 0.
Z K Y
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Konigsberg
2205 posts
#10 • 1 Y
Y by Adventure10
So the probable date is 1 day on June 15 and the 2nd day on June 21, or either June 15 or June 21 may be the starting date?

Thanks! I wish that this would become a success like past year!
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Konigsberg
2205 posts
#11 • 1 Y
Y by Adventure10
Sorry to double post, but are we allowed to not use our AoPS username?
Z K Y
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howie2000
413 posts
#12 • 1 Y
Y by Adventure10
Signups
Z K Y
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chezbgone
1523 posts
#13 • 1 Y
Y by Adventure10
Signups
Z K Y
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pythag011
2453 posts
#14 • 2 Y
Y by Adventure10, Mango247
Signups
Z K Y
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baijiangchen
220 posts
#15 • 2 Y
Y by Adventure10, Mango247
Signups
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