Forum

> > Off Topic > A risky wager.
Forums overviewOff Topic overviewLog in to reply

English A risky wager.

13 replies
To the start Previous 1 Next To the start

old A risky wager.

Lee
Moderator Off Offline

Quote
You are at a party with a friend. There are 20 people present including you and the friend. your friend makes you a wager that there are no two people at this party with the same birthday. Would you make the wager?

Note: Birthdays are identical if their month and date matches up. Year, hour, minute, seconds, are not part of the requirement.
edited 1×, last 14.04.10 07:02:51 am

old Re: A risky wager.

Lee
Moderator Off Offline

Quote
If there are 20 people, would you bet that there are at least 2 people who share the same birthday?

old Re: A risky wager.

ohaz
User Off Offline

Quote
I would do this:
Spoiler >
edited 1×, last 14.04.10 07:20:49 am

old Re: A risky wager.

bezmolvie
User Off Offline

Quote
Well, depends, as at 23 people it just nears 50%, so I want to know how much I'm betting.

old Re: A risky wager.

Lee
Moderator Off Offline

Quote
That's essentially correct, although @TKD: 356 instead of 256 xD.

old Re: A risky wager.

sonnenschein
User Off Offline

Quote
if the party is clearly for a single man, why anyone would even come if they have birthday. they would probably make their own.
also, 20 people are mostly friends and family so you should know when is their bday

old Re: A risky wager.

DC
Admin Off Offline

Quote
nobody said that it is a BIRTHDAYparty
Spoiler >

old Re: A risky wager.

ohaz
User Off Offline

Quote
oh, well, I calculated with the right numbers, just wrote it down the wrong way...
In fact, it's even an unfair game. I calculated the chance, that no two people have the same birthday. So the chance, that two people have the same birthday is 100%- my calculated chance. Depends on which side you have to chose when your friend makes the wager!

old Re: A risky wager.

sonnenschein
User Off Offline

Quote
DC has written
nobody said that it is a BIRTHDAYparty
Spoiler >

ah crap, you are right
I guess that changes alot of things

old Re: A risky wager.

Relapse
User Off Offline

Quote
Bloodshot has written
Well, depends, as at 23 people it just nears 50%, so I want to know how much I'm betting.

did you look that up on wikipedia?

old Re: A risky wager.

YellowBanana
BANNED Off Offline

Quote
Depends on the odds I'm getting.

The chances 2 people don't share the same birthday in a party of 20 people is:

(365!/(365^n (365-n)!)) for n = 20,

so that's about 58.8%. If my odds are better than 10:7, i'm taking it

If the odds are 1:1,

I'm winning 0.588 * (2 * amount) - amount in a long term

old Re: A risky wager.

Banaan
User Off Offline

Quote
I'd certainly take the bet
(knew this one, but then with a football team)
To the start Previous 1 Next To the start
Log in to replyOff Topic overviewForums overview