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Altamira_64
Junior Member

Posts: 116
 Holidays in Bahamas   « on: Oct 10th, 2012, 11:55am » Quote Modify

4 couples are going on holiday in Bahamas to a 5-star hotel. The receptionist gave them four consecutive rooms with numbers 1 to 4. The women went upstairs to choose rooms and stayed to one of the rooms each, while their husbands were having a drink at the bar. After some drinks, they decided to go upstairs to their rooms.
"If we all go upstairs and start opening the 4 doors at random until we find our wife, what are the chances to get to the correct room with 2 attempts each?" asked the first man.

"This is easy", says the second. "Since we will open 2 out of 4 doors, each of us has 50% probability to locate his wife. So, in order for all four of us to make it, the probability is (1/2)^4, that is, 1/16."

"Wrong!" says the third. There is a way to get to the correct room with probability greater than 40% and without havng to communicate with our wives or between us, after the first of us goes upstairs."

What is the method he is suggesting?
 « Last Edit: Oct 10th, 2012, 12:29pm by Altamira_64 » IP Logged
Altamira_64
Junior Member

Posts: 116
 Re: Holidays in Bahamas   « Reply #1 on: Oct 11th, 2012, 7:41am » Quote Modify

Guys, silly question, how do you put this "NEW" flag next to the Riddle Subject??
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towr
wu::riddles Moderator
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Some people are average, some are just mean.

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 Re: Holidays in Bahamas   « Reply #2 on: Oct 11th, 2012, 8:54am » Quote Modify

Not?
Besides, I don't think it's new; I recall a very similar riddle with, I think lockers.

 http://www.ocf.berkeley.edu/~wwu/cgi-bin/yabb/YaBB.cgi?board=riddles_har d;action=display;num=1138457723 [/edit]
 « Last Edit: Oct 11th, 2012, 10:08am by towr » IP Logged

Wikipedia, Google, Mathworld, Integer sequence DB
rmsgrey
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 Re: Holidays in Bahamas   « Reply #3 on: Oct 12th, 2012, 4:32am » Quote Modify

on Oct 11th, 2012, 7:41am, Altamira_64 wrote:
 Guys, silly question, how do you put this "NEW" flag next to the Riddle Subject??

Forum topics are flagged "new" when there's a post in the thread since the last time you viewed it.
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Altamira_64
Junior Member

Posts: 116
 Re: Holidays in Bahamas   « Reply #4 on: Oct 12th, 2012, 7:56am » Quote Modify

OK, so indeed my question was silly

Thanks for clarifying!!
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