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, 2002

Number theory Difficulty 1.0 Junior Find the answer Canada

A perfect number is an integer that is equal to the sum of all of its positive divisors, except itself. For example, 28 is a perfect number because $28 = 1+2+4+7+14$ . Which of the following is a perfect number?

(A) $10$ (B) $13$ (C) $6$ (D) $8$ (E) $9$

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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.