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2021 Kyiv City MO
2021 Kyiv City MO Round 1
9.1
9.1
Part of
2021 Kyiv City MO Round 1
Problems
(1)
Birthday paradox
Source: Kyiv City MO 2021 Round 1, Problem 9.1
12/21/2023
Before the math competition, Dmytro overheard Olena and Mykola talking about their birthdays.О: "The day and month of my birthday are half as large as the day and month of Mykola's birthday." М: "Also, the day of Olena's birth and the month of my birth are consecutive positive integers." О: "And the sum of all these four numbers is a multiple of
17
17
17
."Can Dmitro determine the day and month of Olena's birth?Proposed by Olena Artemchuk and Mykola Moroz
Birthday