Probability Question

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anubhavgulati: Senior | Next Rank: 100 Posts; Posts: 47; Joined: Sun May 29, 2011 5:28 amFollowed by: 1 member; Thanked: 1 times

by anubhavgulati » Fri Jul 22, 2011 8:33 pm

Hi All,

Probability question:

If there are 5 apples, out of which 1 is rotten apple and rest 4 are good apples. What is the probability that if you select 2 apples out of which 1 apple must be a rotten apple.

Please let me know how to solve this question.

Thanks,
Anubhav

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Hi All,
I found the solution, thanks.
######################

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Source: Beat The GMAT — Problem Solving | Fri Jul 22, 2011 8:33 pm

ntamhane: Senior | Next Rank: 100 Posts; Posts: 34; Joined: Thu Jun 30, 2011 4:15 amFollowed by: 1 member; Thanked: 1 times

by ntamhane » Fri Jul 22, 2011 10:02 pm

No. of ways selecting 2 apples is 5!/3!*2! = 10 ways
No. of ways selecting 2 good apples = 4!/2!*2! = 6ways
P(selecting 2 good apples)=6/10
P(selecting 1 rotten apple)=1-(6/10)= [spoiler]2/5[/spoiler]

Whats he OA?

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