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AIME 2013 I #4 — 13-Square Array 8 Red 5 Blue Coloring

1925SpecialistCombinatoricsCounting PrinciplesProbability

AIME I · 2013 · Problem 4

In the array of $13$ squares shown below, $8$ squares are colored red, and the remaining $5$ squares are colored blue. If one of all possible such colorings is chosen at random, the probability that the chosen colored array appears the same when rotated $90^{\circ}$ around the central square is $\frac{1}{n}$ , where $n$ is a positive integer. Find $n$. [Asymptote diagram]
0 students attempted0% solvedRating 1925

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