wu :: forums - Print Page


    
      
        wu :: forums
        (http://www.ocf.berkeley.edu/~wwu/cgi-bin/yabb/YaBB.cgi)
      

        riddles >> hard >> Holidays in Bahamas
        
(Message started by: Altamira_64 on Oct 10^th, 2012, 11:55am)

Title: Holidays in Bahamas
Post by Altamira_64 on Oct 10^th, 2012, 11:55am

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?

Title: Re: Holidays in Bahamas
Post by Altamira_64 on Oct 11^th, 2012, 7:41am

Guys, silly question, how do you put this "NEW" flag next to the Riddle Subject??

Title: Re: Holidays in Bahamas
Post by towr on Oct 11^th, 2012, 8:54am

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

[edit] http://www.ocf.berkeley.edu/~wwu/cgi-bin/yabb/YaBB.cgi?board=riddles_hard;action=display;num=1138457723 [/edit]

Title: Re: Holidays in Bahamas
Post by rmsgrey on Oct 12^th, 2012, 4:32am

on 10/11/12 at 07:41:25, 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.

Title: Re: Holidays in Bahamas
Post by Altamira_64 on Oct 12^th, 2012, 7:56am

OK, so indeed my question was silly :-[

Thanks for clarifying!!