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Ukraine Contests
Official Ukraine Selection Cycle
Kyiv City MO
2021 Kyiv City MO
2021 Kyiv City MO Round 1
7.1
7.1
Part of
2021 Kyiv City MO Round 1
Problems
(1)
We balling
Source: Kyiv City MO 2021 Round 1, Problem 7.1
12/21/2023
Mom brought Andriy and Olesya
4
4
4
balls with the numbers
1
,
2
,
3
1, 2, 3
1
,
2
,
3
and
4
4
4
written on them (one on each ball). She held
2
2
2
balls in each hand and did not know which numbers were written on the balls in each hand. The mother asked Andriy to take a ball with a higher number from each hand, and then to keep the ball with the lower number from the two balls he took. After that, she asked Olesya to take two other balls, and out of these two, keep the ball with the higher number. Does the mother know with certainty, which child has the ball with the higher number?Proposed by Bogdan Rublov
combinatorics
game
balls