Library / /224 of 472

, 1999

Combinatorics Difficulty 2.0 Junior Find the answer Canada

If $(a+b+c+d+e+f+g+h+i)^2$ is expanded and simplified, how many different terms are in the final answer?

(A) $36$ (B) $9$ (C) $45$ (D) $81$ (E) $72$

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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.