This website contains problems from math contests. Problems and corresponding tags were obtained from the Art of Problem Solving website.

Tags were heavily modified to better represent problems.

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OR:
NO:

Found problems: 3

2021 Taiwan APMO Preliminary First Round, 3
Tags: possibility , combinatorics
Let a board game has $10$ cards: $3$ [b]skull[/b] cards, $5$ [b]coin[/b] cards and $2$ [b]blank[/b] cards. We put these $10$ cards downward and shuffle them and take cards one by one from the top. Once $3$ [b]skull[/b] cards or [b]coin[/b] cards appears we stop. What is the possibility of it stops because there appears $3$ [b]skull[/b] cards?

2023 China Second Round, 7
Tags: possibility , dice
We throw a dice three times and the numbers are $x,y,z$ find out the possibility of $\binom{7}{x}<\binom{7}{y}<\binom{7}{z}$

2018 Taiwan APMO Preliminary, 4
Tags: combinatorics , possibility
If we fill $1\sim 16$ into $4\times4$ chessboard randomly. What is the possibility of the sum of each rows and columns are all even?