SOLUTION: 13. Hans has 12 good friends, five of them male and seven of them female. He decides to have a dinner party but can invite only seven because his dining room table will seat only e

Question 306089: 13. Hans has 12 good friends, five of them male and seven of them female. He decides to have a dinner party but can invite only seven because his dining room table will seat only eight people. He decides to invite his guestes by lot. What is the probability that
a) There will be four males and four females at the party?
b) Rivka will be among those invited?
c) Hans will have only female guests?
Textbook answers:
13 a)0.44
b) 7/12
c) 1/792
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
Hans has 12 good friends, five of them male and seven of them female.
Comment: I guess we have to assume that Hans is one of the males present.
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He decides to have a dinner party but can invite only seven because his dining room table will seat only eight people. He decides to invite his guestes by lot. What is the probability that
a) There will be four males and four females at the party?
Pick 3 males in 5C3 = 10 ways
Pick 4 females in 7C4 = 35 ways
Randomly pick 7 guests: 12C7 = 792 ways
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P(4 m, 4f)= (10*35)/792 = 0.4419
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b) Rivka will be among those invited?
I don't see how they came up with 7/792
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c) Hans will have only female guests?
Pick 7 females = 7C7 = 1
P(7 females) = 1/792
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Cheers,
Stan H.
=========================
Textbook answers:
13 a)0.44
b) 7/12
c) 1/792
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