Tuesday puzzle

[EternalOptimist]

Depends, is it a goat ?

you're not from round here are you ?

[russell]

Question. If I have five pairs of pants. One red, one green, one blue, one pink and one black.

What is the probability I am wearing the pink pair today?

100%

[EternalOptimist]

ok

the answer is 1 in 3


but what if they had said it was the oldest child that was a girl ?

what is the answer now ?

[Moose423956]

ok

the answer is 1 in 3


but what if they had said it was the oldest child that was a girl ?

what is the answer now ?

50%

[eek]

If you were chatting to someone, and they mentioned that they had two kids, one of which was a girl

what are the chances that the other kid is also a girl ?

48.7% based on the accepted birth ratio of 105 boys to 100 girls. This changes dramatically if you are in India or China due to infanticide.

It really depends on the context of how the information was received. Given the phrasing you used I think the odds of the other child being a girl is 0%.

[MarillionFan]

48.7% based on the accepted birth ratio of 105 boys to 100 girls. This changes dramatically if you are in India or China due to infanticide.

It really depends on the context of how the information was received. Given the phrasing you used I think the odds of the other child being a girl is 0%.

Eek 1 - EternalOptimist 0

[stek]

ok

the answer is 1 in 3

50% surely?!!

[eek]

ok

the answer is 1 in 3


but what if they had said it was the oldest child that was a girl ?

Its not 1 in 3 the odds are 48.7% as the sex of both children are "independent" random events.

so same answer both times.

[EternalOptimist]

no, according to my book on advanced statistics , the answer to the first puzzle is 1 in 3
and the second is 50/50



here's my sock one - assume its pitch black and you have ten white socks and ten black socks in a drawer, how many do you have to take out to ensure that you get a pair?

[MarillionFan]

no, according to my book on advanced statistics , the answer to the first puzzle is 1 in 3
and the second is 50/50



here's my sock one - assume its pitch black and you have ten white socks and ten black socks in a drawer, how many do you have to take out to ensure that you get a pair?

But you have assumed that these are 50/50 probabilities to which Eek has proved they are not.

So in fact your book is wrong. It has made an incorrect assumption.