12 thoughts on “Pigeonhole Principle – 2

  1. Hi J,
    In the gloves question.
    How does case a and b differ from each other.
    I am not able to differentiate the situations or rather the answers.
    A) We need only 4 chances. Why am I not exhausting all the pairs not required by me and then getting the one that is favourable. Ans would then be 37

  2. I am getting 37 for the third question in the exercise.
    worst-case scenario should be picking 9 cards of each suit = 9*4 + 1 ?

    Where am I going wrong ?


  3. the worst case situation for last question will be 3 face cards..and as suite is not mentioned at all… ‘so three face cards from all suits’….. i.e. 3×4 = 12 + 1 = 13

    • Because we want four non-face cards, not just one. So in the worst case, I might pick up 12 face cards, I need at least 4 more to guarantee 4 non-face cards.


  4. Sir, Can we do this question using Pigeonhole principle? I’m not able to come across the worst case in here, any hints, please?

    There are 120 boxes, each of which contains any number of tennis balls, from a minimum of 130 to a maximum of 155. The maximum number of boxes containing the same number of tennis balls is at least

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