Maths Olympiad Prep

Library / /331 of 413

, 2006

Combinatorics Difficulty 2.0 Junior Find the answer Canada

The 88 people at a party shook hands exactly once with each of the others before the ninth person arrived. The ninth person then shook hands with some of these 88 people. A total of 3232 handshakes took place. With how many people did the ninth person shake hands?

(A) 33 (B) 44 (C) 55 (D) 66 (E) 77

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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.