2019 AMC 12B Problem 2


Consider the statement, “If nn is not prime, then n2n-2 is prime.” Which of the following values of nn is a counterexample to this statement?

(A) 11(B) 15(C) 19(D) 21(E) 27\textbf{(A) } 11 \qquad \textbf{(B) } 15 \qquad \textbf{(C) } 19 \qquad \textbf{(D) } 21 \qquad \textbf{(E) } 27


Full credit goes to MAA for authoring these problems. These problems were taken on the AOPS website.

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Problem Tags: Number theory

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Category: AMC 12B
Points: 2
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