Jump to content


Welcome to BrainDen.com - Brain Teasers Forum

Welcome to BrainDen.com - Brain Teasers Forum. Like most online communities you must register to post in our community, but don't worry this is a simple free process. To be a part of BrainDen Forums you may create a new account or sign in if you already have an account.
As a member you could start new topics, reply to others, subscribe to topics/forums to get automatic updates, get your own profile and make new friends.

Of course, you can also enjoy our collection of amazing optical illusions and cool math games.

If you like our site, you may support us by simply clicking Google "+1" or Facebook "Like" buttons at the top.
If you have a website, we would appreciate a little link to BrainDen.

Thanks and enjoy the Den :-)
Guest Message by DevFuse
 

Photo
- - - - -

A society that prizes girls


Best Answer bonanova, 21 February 2013 - 04:23 AM

Spoiler for Think bonanova and prime are correct

 

Since it's solved, I won't spoiler this.

 

The answer is not complex. Every birth, regardless of anything that is said, done, legislated, prohibited, presupposed, calculated, imagined or hoped for, has equal chances of being a boy or girl.

 

If you flip a coin an odd number of times, then, yes, the number of heads and tails cannot be equal. But the question is for large numbers of conceptions and births - for a society - where, even though the numbers of boys and girls may not be exactly equal at every moment - each birth changes the running total - the chances of an excess of boys exactly equals the chances of an excess of girls. The question asks whether a birth control strategy can affect the society's overall gender balance in a systematic way. The answer is no, it can not.

 

No calculus needed. ^_^

Go to the full post


  • Please log in to reply
13 replies to this topic

#1 BMAD

BMAD

    Senior Member

  • Members
  • PipPipPipPip
  • 1702 posts
  • Gender:Female

Posted 20 February 2013 - 06:30 AM

In a society in which people only want girls every family continues to have children until they have a girl. If they have a boy, they have another child. If they have a girl, they stop. What is the proportion of girls to boys in this society?
  • 0

#2 bonanova

bonanova

    bonanova

  • Moderator
  • PipPipPipPip
  • 5918 posts
  • Gender:Male
  • Location:New York

Posted 20 February 2013 - 09:14 AM

Spoiler for Looks like


  • 0
The greatest challenge to any thinker is stating the problem in a way that will allow a solution.
- Bertrand Russell

#3 witzar

witzar

    Advanced Member

  • Members
  • PipPipPip
  • 233 posts

Posted 20 February 2013 - 11:40 AM

Spoiler for reversal


  • 0

#4 BMAD

BMAD

    Senior Member

  • Members
  • PipPipPipPip
  • 1702 posts
  • Gender:Female

Posted 20 February 2013 - 01:40 PM


Spoiler for reversal

there is a 50% chance of having a boy or girl in this society since it wasn't implied. I should had stated it as being stacked in the favor of boys to make the ratio more fun, but oh well

Edited by BMAD, 20 February 2013 - 01:41 PM.

  • 0

#5 Yoruichi-san

Yoruichi-san

    "That Woman"

  • Members
  • PipPipPipPip
  • 3395 posts
  • Gender:Not Telling
  • Location:Outside the box

Posted 20 February 2013 - 07:02 PM

Spoiler for Series are not my strong point...


  • 0
Women are definitely stronger. We are [Fe]males, after all...

Some of what makes me me is real, some of what makes me me is imaginary...I guess I'm just complex. ;P

<3 BBC's Sherlock, the series and the man. "Smart is the new sexy."

Chromatic Witch links now on my 'About Me' page! Episode 3 is finally here!

When life hands me lemons, I make invisible ink.

#6 Prime

Prime

    Senior Member

  • Members
  • PipPipPipPip
  • 872 posts
  • Gender:Male
  • Location:Illinois, US

Posted 20 February 2013 - 07:08 PM

The number of people in the society is not specified either. I assume, there are n married couples.

Spoiler for my calculation

 


  • 0

Past prime, actually.


#7 Prime

Prime

    Senior Member

  • Members
  • PipPipPipPip
  • 872 posts
  • Gender:Male
  • Location:Illinois, US

Posted 20 February 2013 - 07:35 PM

Oops, seems I messed up again.

Spoiler for More girls

 


  • 0

Past prime, actually.


#8 bonanova

bonanova

    bonanova

  • Moderator
  • PipPipPipPip
  • 5918 posts
  • Gender:Male
  • Location:New York

Posted 20 February 2013 - 07:41 PM

Spoiler for Consider


  • 0
The greatest challenge to any thinker is stating the problem in a way that will allow a solution.
- Bertrand Russell

#9 bushindo

bushindo

    Senior Member

  • VIP
  • PipPipPipPip
  • 721 posts
  • Gender:Male
  • Location:Los Angeles, CA

Posted 20 February 2013 - 09:17 PM

Spoiler for Series are not my strong point...


The number of people in the society is not specified either. I assume, there are n married couples.

Spoiler for my calculation

 
I think there is a discrepancy with bonanova's answer because...

Spoiler for


  • 0

#10 Prime

Prime

    Senior Member

  • Members
  • PipPipPipPip
  • 872 posts
  • Gender:Male
  • Location:Illinois, US

Posted 20 February 2013 - 09:18 PM

Spoiler for Marriage procedure

  • 0

Past prime, actually.





0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users