The second time the game is played, the person who calls the number 50 is the winner. If Xavier goes first, how does he guarantee that he will win?
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puts 2,604 problems in a working order, from Junior Challenge level to the IMO shortlist.
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.