I get about 1/1772 but I’m not confident

  • pixelscience@lemm.ee
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    6 months ago

    Put it in ChatGPT, just for fun…

    To find the probability of drawing 7 or more face cards (which includes Jacks, Queens, Kings, and Aces) from 8 random cards, we first need to recognize that in a standard deck of 52 cards, there are 16 face cards (4 each of Jacks, Queens, Kings, and Aces) and 36 non-face cards.

    We need to calculate the probabilities of two cases:

    1. Drawing exactly 7 face cards and 1 non-face card.
    2. Drawing 8 face cards.

    For both, we can use the hypergeometric distribution. The general formula for the hypergeometric probability is:

    [ P(X = k) = \frac{{\binom{K}{k} \binom{N-K}{n-k}}}{{\binom{N}{n}}} ]

    Where:

    • ( N ) is the total number of items (cards in the deck, 52),
    • ( K ) is the total number of items of one type (face cards, 16),
    • ( n ) is the number of items to be drawn (8),
    • ( k ) is the number of items of one type to be drawn.

    For 7 face cards: [ P(X = 7) = \frac{{\binom{16}{7} \binom{36}{1}}}{{\binom{52}{8}}} ]

    For 8 face cards: [ P(X = 8) = \frac{{\binom{16}{8} \binom{36}{0}}}{{\binom{52}{8}}} ]

    We will calculate these probabilities to get the final answer.

    The probability of drawing 7 or more face cards (Jacks, Queens, Kings, Aces) from 8 random playing cards is approximately 0.0564%, or about 1 in 1772. This is a rare event given the small proportion of face cards in a standard deck.