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hl1711
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Probability 01 Aug 2008, 16:25
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Hi,

If 2 people are to create a user name made up of 7 characters (can use any of the 26 alphabets or the 10 digits, repeats allowed). What is the probability that these 2 people will create the exact same user name (assuming that these people don't know each other at all)?

Thanks!



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durgesh79
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Probability 01 Aug 2008, 17:35
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hl1711
Hi,

If 2 people are to create a user name made up of 7 characters (can use any of the 26 alphabets or the 10 digits, repeats allowed). What is the probability that these 2 people will create the exact same user name (assuming that these people don't know each other at all)?

Thanks!
Show more


since repeates are allowed, there are 36^7 different usernames possible ... lets call them 1,2,3.......36^7
our 2 people are A and B....

Probablity that A takes 1 and B also takes 1 = 1/36^7 * 1/36^7
Probability that A takes 2 and B also takes 2 = 1/36^7 * 1/36^7
similarly other .... from 1 to 36^7

final probability = 36^7 * (1/36^7 * 1/36^7) = 1/36^7
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hl1711
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Probability 01 Aug 2008, 22:25
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durgesh79
hl1711
Hi,

If 2 people are to create a user name made up of 7 characters (can use any of the 26 alphabets or the 10 digits, repeats allowed). What is the probability that these 2 people will create the exact same user name (assuming that these people don't know each other at all)?

Thanks!


since repeates are allowed, there are 36^7 different usernames possible ... lets call them 1,2,3.......36^7
our 2 people are A and B....

Probablity that A takes 1 and B also takes 1 = 1/36^7 * 1/36^7
Probability that A takes 2 and B also takes 2 = 1/36^7 * 1/36^7
similarly other .... from 1 to 36^7

final probability = 36^7 * (1/36^7 * 1/36^7) = 1/36^7
Show more

You folks are amazing! Thanks so much.



Archived Topic
Hi there,
This topic has been closed and archived due to inactivity or violation of community quality standards. No more replies are possible here.
Where to now? Join ongoing discussions on thousands of quality questions in our Quantitative Questions Forum
Still interested in this question? Check out the "Best Topics" block above for a better discussion on this exact question, as well as several more related questions.
Thank you for understanding, and happy exploring!