SOLUTION: Three students are selected, one after anoth er, from a class of 10 boys and 5 girls. a) Find the probability that the first two are boys and the third is a girl b) Find the pr

Algebra ->  Permutations -> SOLUTION: Three students are selected, one after anoth er, from a class of 10 boys and 5 girls. a) Find the probability that the first two are boys and the third is a girl b) Find the pr      Log On


   

Question 918557: Three students are selected, one after anoth
er, from a class of 10 boys and 5 girls.
a) Find the probability that the first two are boys and the third is a girl
b)
Find the probability that
all three are of the same sex
c)
Find the probability that
only the first and third are of the same sex
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
Three students are selected, one after anoth
er, from a class of 10 boys and 5 girls.
a) Find the probability that the first two are boys and the third is a girl
Ans: (10/15)(9/14)(5/13)
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b)
Find the probability that
all three are of the same sex
Ans: [10C3 + 5C3]/15C3
c)
Find the probability that
only the first and third are of the same sex
Patterns:: bgb or gbg
(10/15)(5/14)(9/13) + (5/15)(10/14)(4/13)
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Cheers,
Stan H.
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