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Probability

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Probability

by serenayc » Wed May 09, 2012 8:56 pm
John and Peter are among the 9 players a basketball coach can choose from to field a 5-player team. If all 5 players are chosen at random, what is the probability of choosing a team that includes John and Peter?

A) 1/9 B)1/6 c)2/9 d)5/18 e)1/3
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by aneesh.kg » Wed May 09, 2012 9:04 pm
Required probability = (Number of ways of selecting a team with John and Peter)/(Number of ways of selecting a team of five from nine people)

Number of ways of selecting a team with John and Peter is found by selecting John and Peter first (by 2C2 ways) AND (so multiplication) then selecting the remaining 3 players required in the team from the remaining 7 people available(by 7C3 ways). So the total number of such ways is 2C2*7C3

Number of ways of selecting a team of 5 from 9 is 9C5.

Required probability
= (2C2*7C3)/(9C5)
= (1*7*5)/(9*2*7)
= 5/18

[spoiler](D)[/spoiler] is the answer
Aneesh Bangia
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