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k a May Highlights and 2025 AoPS Online Class Information
jlacosta   0
May 1, 2025
May is an exciting month! National MATHCOUNTS is the second week of May in Washington D.C. and our Founder, Richard Rusczyk will be presenting a seminar, Preparing Strong Math Students for College and Careers, on May 11th.

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[*]May 21st, 4:00pm PT/7:00pm ET, Mathcamp 2025 Qualifying Quiz Part 2 Math Jam, Problems 5 and 6, Canada/USA Mathcamp staff will discuss solutions to Problems 5 and 6 of the 2025 Mathcamp Qualifying Quiz![/list]
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0 replies
jlacosta
May 1, 2025
0 replies
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Easy Probability Question with sol
PikaVee   5
N 14 minutes ago by PikaVee
If there was a Pokemon battle where you had a Pikachu that was level 25 with only one move being Thunder with a 70% chance of hitting against a lv 28 1 HP Squirtle that has a 2 x weakness against Electric Type move and outspeeds your Pikachu with 4 total moves. Protect, Tackle, Water Gun and Rain Dance each with an equal chance of happening. The chances of it happening is a/b where a and b are coprime. What is ab?(Note: Only Protect can make the opposing Pokemon immune for one turn)


It is easier to find out the chances of the pokemon fainting in one turn than not so I will start with that. The chance of Pikachu using the move successfully is a 70% chance or $ \frac{7}{10} $ to hit and $ \frac{3}{4} $ that the opposing pokemon will use a not useful move. So $ \frac{7}{10} * \frac{3}{4} = \frac{21}{40} $ so the chances that the opposing pokemon will live for this turn is $1 - \frac{21}{40} $ or $ \frac{19}{40} $. Now that we have a and b we multiply them and $19*40=760$


5 replies
PikaVee
May 28, 2025
PikaVee
14 minutes ago
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Overly wordy problems
ZMB038   15
N 17 minutes ago by Rita.Y
Hey everyone, here we can post questions with way to many extraneous words, that are actually easy.
Try to solve the one above yours.
I'll start:
Click to reveal hidden text
15 replies
ZMB038
May 28, 2025
Rita.Y
17 minutes ago
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prime numbers
wpdnjs   128
N 2 hours ago by Yihangzh
does anyone know how to quickly identify prime numbers?

thanks.
128 replies
wpdnjs
Oct 2, 2024
Yihangzh
2 hours ago
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Problem of the day
sultanine   20
N 2 hours ago by EthanNg6
[center]Every day I will post 3 new problems
one easy, one medium, and one hard.
Please hide your answers so others won't be affected
:D :) :D :) :D
20 replies
sultanine
May 23, 2025
EthanNg6
2 hours ago
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No more topics!
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bracelets
pythagorazz   7
N Apr 22, 2025 by H1u2g4o4
Kat designs circular bead bracelets for kids. Each bracelet has 5 beads, all of which are either yellow or green. If beads of the same color are identical, how many distinct bracelets could Kat make?
7 replies
pythagorazz
Apr 14, 2025
H1u2g4o4
Apr 22, 2025
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bracelets
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pythagorazz
382 posts
pythagorazz
#1 h  Apr 14, 2025, 9:09 AM
Y by
Kat designs circular bead bracelets for kids. Each bracelet has 5 beads, all of which are either yellow or green. If beads of the same color are identical, how many distinct bracelets could Kat make?
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Bobelix
40 posts
Bobelix
#2 h  Apr 14, 2025, 10:41 AM
Y by
I could be wrong, but isn’t it 32?
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HungryCalculator
541 posts
HungryCalculator
#3 h  Apr 14, 2025, 12:04 PM • 2 Y
Y by orangefronted, pythagorazz
1+1+2+2+1+1=8
Bobelix wrote:
I could be wrong, but isn’t it 32?

Account for rotations for each case of # of yellow and green beads
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EthanNg6
54 posts
EthanNg6
#4 h  Apr 22, 2025, 2:07 AM
Y by
It's 32
2 times 2 times 2 times 2 times 2=32
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DDCN_2011
354 posts
DDCN_2011
#5 h  Apr 22, 2025, 2:35 AM
Y by
EthanNg6 wrote:
It's 32
2 times 2 times 2 times 2 times 2=32

like what 2 post ahead said you have to account for rotation as ygygy will be counted multiple times as rotations
This post has been edited 1 time. Last edited by DDCN_2011, Apr 22, 2025, 2:35 AM
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That_One_Genius.
15 posts
That_One_Genius.
#6 h  Apr 22, 2025, 3:35 AM
Y by
I might be wrong, but isn't it 6(not counting symmetries)?
Solution
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maxamc
588 posts
maxamc
#7 h  Apr 22, 2025, 12:47 PM
Y by
That_One_Genius. wrote:
I might be wrong, but isn't it 6(not counting symmetries)?
Solution

how about 5y, 5g
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H1u2g4o4
1 post
H1u2g4o4
#8 h  Apr 22, 2025, 4:06 PM
Y by
Yellow Green Circular arrangement Number of types
Yellow Green
5 0 1
4 1 1
3 2 2
2 3 2
1 4 1
0 5 1

all:8
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