Interesting Question of the Day – 3 January 2018

In the land of Misogynia, parents only want to have boys.

If they have a boy, they stop having children.

If they have a girl, they keep trying to have a boy.

Out of 100 births, how many would be statistically likely to be girls?  (We are assuming there is no technology to increase the chance of a boy or to abort a girl.)

The first new player to comment on the website with the correct answer wins a free drink at their next iQ Trivia show.

Tagged with: , ,
6 comments on “Interesting Question of the Day – 3 January 2018
  1. Andrew B says:

    Fifty.

    Even aside from all of that infinite series mumbo-jumbo, each birth is assumed to be a random draw with replacement. Collect any 100 births at random and the ratio should stay the same… all you’re doing is eliminating big brothers!

  2. Ally says:

    It’d be pretty impressive to keep procreating if there’s only boys…

    • iqtrivia says:

      We’re not saying it’s a likely scenario, but however you slice it, it would wind up being an even gender split.

  3. Nathan says:

    I suspect this is a trick question.

    If every birth is a new binary event (boy or girl) that is independent of any previous observation (have they had a boy yet or not), then there should be a 50:50 split per hundred.

    I would have thought the only thing that would be skewed in the land of Misogynia would be the size of some broods. Half the families would have 1 child, a quarter would have 2 and so on.

    • iqtrivia says:

      Yes each birth is subject to random chance and you’d have an even split.

      And, as you pointed out, some very odd family sizes.