In: Statistics and Probability
A standard deck of cards consists of four suits (clubs,
diamonds, hearts, and spades), with each suit containing 13 cards
(ace, two through ten, jack, queen, and king) for a total of 52
cards in all.
a.) How many 7-card hands will consist of exactly 3 kings and 2
queens?
b.) What is the probability of getting a 7-card hand that consists
of exactly 3 kings and 2 queens? (Note: Enter your answer as a
fraction.)
Number of kings in a deck of cards =4
Number of queens in a deck of cards = 4
Number of cards others than kings and queens = 52 - 4 - 4 = 52-8=44
Number of cards in a hand = 7
a)
Number of 7-card hands will consist of exactly 3 kings and 2 queens (other two cards are to be other than king and queen)
= Number of ways of getting 3 kings from 4 kings x
Number of ways of getting 2 queens from 4 queens x
Number of ways getting 2 cards other than kings and queens from 44 cards other than kings and queens
=
Number of 7-card hands will consist of exactly 3 kings and 2 queens = 22704
b)
Probability of getting a 7-card hand that consists of exactly 3 kings and 2 queens
= Number of 7-card hands will consist of exactly 3 kings and 2 queens / Number of 7-card hands
Number of 7-card hands = Number of ways of getting 7 cards from 52 cards =
From (a)
Number of 7-card hands will consist of exactly 3 kings and 2 queens = 22704
Probability of getting a 7-card hand that consists of exactly 3 kings and 2 queens
= Number of 7-card hands will consist of exactly 3 kings and 2 queens / Number of 7-card hands
=22704/133784560 = 1419/8361535
Probability of getting a 7-card hand that consists of exactly 3 kings and 2 queens