ONE
    Númas
    ← Back to the programme
    OlympiadHardCombinatorics7–9

    From the numbers 11 to 2020, how many must be chosen to be certain that two of the chosen numbers are consecutive?

    Dos números 11 a 2020, quantos é preciso escolher para ter a certeza de que dois dos escolhidos são consecutivos?

    Answer options

    Solution

    Step 1 of 3

    1. 1.The ten odd numbers 1,3,5,…,191, 3, 5, \ldots, 19 contain no consecutive pair, so 1010 choices can still fail.