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2025 AMC 12A Question 13

AMC12 · 2025 AMC 12A

Question 13

Let $C = \{1, 2, 3, \ldots, 13\}.$ Let $N$ be the greatest integer such that there exists a subset of $C$ with $N$ elements that does not contain five consecutive integers. Suppose $N$ integers are chosen at random from $C$ without replacement. What is the probability that the chosen elements do not include five consecutive integers?
  1. $\dfrac{3}{130}$
  2. $\dfrac{3}{143}$
  3. $\dfrac{5}{143}$
  4. $\dfrac{1}{26}$
  5. $\dfrac{5}{78}$