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Probability question

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by thegmatbeater » Tue Aug 26, 2008 11:08 am
36. A drawer holds 4 red hats and 4 blue hats. What is the probability of getting exactly three red hats or exactly three blue hats when taking out 4 hats randomly out of the drawer and immediately returning every hat to the drawer before taking out the next?

(a) 1/8
(b) ¼
(c) ½
(d) 3/8
(e) 7/12
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Source: — Problem Solving |

Re: Probability question

by GoMBA » Tue Aug 26, 2008 11:38 am
My take: 1/4

Probability of exactly 3 red hats = 4c1/8c1 * 4c1/8c1 * 4c1/8c1 = 1/8
Similarly,
Probability of exactly 3 blue hats = 4c1/8c1 * 4c1/8c1 * 4c1/8c1 = 1/8

Together the probability of 3 red or 3 blue = 1/8 + 1/8 = 1/4
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Re: Probability question

by sudhir3127 » Tue Aug 26, 2008 11:42 am
thegmatbeater wrote:36. A drawer holds 4 red hats and 4 blue hats. What is the probability of getting exactly three red hats or exactly three blue hats when taking out 4 hats randomly out of the drawer and immediately returning every hat to the drawer before taking out the next?

(a) 1/8
(b) ¼
(c) ½
(d) 3/8
(e) 7/12
chk the link

https://www.beatthegmat.com/probability- ... html#70465
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by Suyog » Tue Aug 26, 2008 11:47 am
@sudhir3127

Can you comment on the raunekk's post in that link.
I did it same way and messed it up somewhere.
Please let me know. Thanks!
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