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        riddles >> easy >> Who survives
        
(Message started by: navdeep1771 on Nov 12^th, 2016, 10:06am)

Title: Who survives
Post by navdeep1771 on Nov 12^th, 2016, 10:06am

100 people are standing in a circle. The person standing at number 1 is having a sword. He kills the person next to him with the sword and then gives the sword to the third person. This process is carried out till there is just one person left. Can you find out who survives?

Title: Re: Who survives
Post by towr on Nov 12^th, 2016, 11:41am

Yes. :P

Title: Re: Who survives
Post by alien2 on Nov 12^th, 2016, 12:24pm

on 11/12/16 at 10:06:13, navdeep1771 wrote:

Can you find out who survives?

Survivors always survive.

Title: Re: Who survives
Post by dudiobugtron on Nov 12^th, 2016, 1:49pm

If 1 person is standing in a circle, are they next to themselves?

Title: Re: Who survives
Post by rloginunix on Nov 12^th, 2016, 1:51pm

Hm. Something to do with Strip Teez (https://www.ocf.berkeley.edu/~wwu/cgi-bin/yabb/YaBB.cgi?board=riddles_cs;action=display;num=1470414283)? But I am not so sure. May be you do not have to take off, khm, sorry, rotate everything - just a bit will do?

Title: Re: Who survives
Post by pex on Nov 12^th, 2016, 4:35pm

The formula given here (https://en.wikipedia.org/wiki/Josephus_problem) says it's the [hide]73rd[/hide] person. I'm not going to bother checking...

Edit: And of course just now I realized how rloginunix hinted at the same solution. Shouldn't post in the morning.

Title: Re: Who survives
Post by navdeep1771 on Nov 12^th, 2016, 10:13pm

Again pex got the right answer.
Well done pex.

However, it can be solved by simple math (without any formula)

Here's the solution:-
[hide]Till the number is the power of 2, the last person to survive will be the one who started it. But since the number here is not the power of 2, we will take the greatest power of 2 that is less than the number which is 64.
100-64 = 36
So 36 people are killed as 2, 4, 6, ...,72. Thus the sword will now be given to the 73rd person. Now he is the first person to start in the remaining 64 people. Thus "73rd person" will be the one to survive.[/hide]

Title: Re: Who survives
Post by alien2 on Nov 13^th, 2016, 1:37am

on 11/12/16 at 22:13:52, navdeep1771 wrote:

[hide]Thus "73rd person" will be the one to survive.[/hide]

[hide]73rd person[/hide] always survives. And a [hide]bartender.[/hide]

Title: Re: Who survives
Post by Grimbal on Nov 21^st, 2016, 4:00am

This solution implies that at some point there are 3 people, A B C, A kills B and then hands over the sword to C. No way! A would kill both B and C. There will be no witness anyway.

If I were among the hundred and at any time I am handed the sword, I certainly won't let anyone of these crazy people take it away from me.

More likely, if #1 kills #2 and hands the sword to #3, #1 gets arrested on the spot and everyone but #2 suvives.

Title: Re: Who survives
Post by alien2 on Dec 4^th, 2016, 10:22am

Quote:

Who survives

If WHO, that is, Wanker Hump Obama survives, the two presidents joined together into one body, I guess the real question is, who wants to survive? Did I say Hump? I meant Trump.