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, 2001

Number theory Difficulty 1.0 Junior Find the answer Canada

A prime number is called a “Superprime” if doubling it, and then subtracting 1, results in another prime number. The number of Superprimes less than 15 is

(A) $2$ (B) $3$ (C) $4$ (D) $5$ (E) $6$

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Source: CEMC, University of Waterloo, licensed CC-BY-NC-4.0. Statement reproduced verbatim; metadata (topic, difficulty) added by this project. Solutions are the publisher's, linked not copied.