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our players Blanche, Dorothy, Rose, and Sophia are playing bridge. An outcome is a particular partition of the $52$ cards into assignment of $13$ cards each to the $4$ players. Leave your answers in factorials.

  • (a) Let $𝑆$ be sample space. Count the number of possible outcomes.
  • (b) Let $𝐴$ be the event that each player gets an ace. How many possible outcomes are there in $𝐴$?
  • (c) Let $𝐵$ (respectively $𝐷$, $𝑅$ and $𝐻$) be the events that Blanche (respectively Dorothy, Rose and Sophie) have at least one ace. Count the number of outcomes in $B\cup D\cup R\cup H$.
  • (d) Count the number of possible outcomes in 𝐵 ∩ (𝐷 ∪ 𝑅 ∪ 𝐻)𝑐.

The question I really need the most help with is d, but I just want to make sure my other answers for the questions are correct as well.

  • For a, I got $\binom{52}{13}\binom{39}{13}\binom{26}{13}$. After choosing $13$ cards to give to a player, you must replace them leaving $n-13$ for the next player.

  • For b, I got $4\cdot 3\cdot 2\cdot 1 = 24$ outcomes- There are $4$ aces, and if we give $1$ to a player it leaves $3$ that the next player can get, etc.

  • For c, we add the possibilities that a player has $1, 2, 3,$ and $4$ aces, then multiple by the number of players.

For d, I'm not exactly sure how to go about it. How can I find the complement of possible outcomes like this? Thank you!

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  • $\begingroup$ Does the c denote complement of $(D\cup R\cup H)$? $\endgroup$
    – AlvinL
    Commented Sep 16, 2023 at 5:36
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    $\begingroup$ (a) is right. For (b), there are $4!=24$ ways to assign the aces, but you need to count the ways to place the other cards, too. And (c) wants to know how many outcomes give someone at least one ace… but isn’t that all outcomes? $\endgroup$
    – mjqxxxx
    Commented Sep 16, 2023 at 5:54

1 Answer 1

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Just addressing (d). $X$ denotes the event that $X$ has at least one ace in hand. Therefore $$ D\cup R\cup H $$ denotes the event that Dorothy has at least one ace OR Rose has at least one ace OR Sophie has at least one ace. Negate this statement to obtain: Dorothy has no aces AND Rose has no aces AND Sophie has no aces.

How many possibilities are there such that Blanche has at least one ace AND the three remaining players have no aces? (Blanche must have all four aces)

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