View Full Version : Tuesday puzzle

EternalOptimist

17th May 2011, 13:17

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 ?

:rolleyes:

SimonMac

17th May 2011, 13:23

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 ?

:rolleyes:

Is the answer The Spanish Inquisition?!

EternalOptimist

17th May 2011, 13:24

Is the answer The Spanish Inquisition?!

that is indeed the answer, but not to this question

russell

17th May 2011, 13:26

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 ?

:rolleyes:

36.756%

OwlHoot

17th May 2011, 13:26

When you say "tuesday's puzzle", was the girl born on a tuesday (http://www.decisionsciencenews.com/2010/05/28/tuesdays-child-is-full-of-probability-puzzles/) ?

I have two children. One is a boy born on a Tuesday. What is the probability I have two boys? The first thing you think is “What has Tuesday got to do with it?” Well, it has everything to do with it.

:rolleyes:

MarillionFan

17th May 2011, 13:29

33.33%

MarillionFan

17th May 2011, 13:30

33.33%

Or Tinky Winky.

SimonMac

17th May 2011, 13:32

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 ?

:rolleyes:

1 in 3

In a two child family the possibilites are:

BB

BG

GB

GG

The first is a girl so that rules out BB

Leaving

BG

GB

GG

As two of those three possibilities include a boy what is left is 1 in 3

amcdonald

17th May 2011, 13:32

Depends, is it a goat ?

MarillionFan

17th May 2011, 13:35

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?

EternalOptimist

17th May 2011, 13:36

Depends, is it a goat ?

:eyes

you're not from round here are you ?

:rolleyes:

russell

17th May 2011, 13:36

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

17th May 2011, 13:37

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 ?

:rolleyes:

Moose423956

17th May 2011, 13:39

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 ?

:rolleyes:

50%

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 ?

:rolleyes:

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

17th May 2011, 13:44

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

:laugh

ok

the answer is 1 in 3

:rolleyes:

50% surely?!!

ok

the answer is 1 in 3

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

:rolleyes:

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

17th May 2011, 13:53

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?

:rolleyes:

MarillionFan

17th May 2011, 13:55

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?

:rolleyes:

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.

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?

:rolleyes:

Three!

I read that in Whizzer and Chips Annual in 1966. Advanced Stats or what!!?

EternalOptimist

17th May 2011, 14:00

Three!

I read that in Whizzer and Chips Annual in 1966. Advanced Stats or what!!?

:rollin:

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?

:rolleyes:

3 unless the first two socks are joined together in the way most sane people store socks.

I'm now waiting for the question regarding three sweet jars (red, black and mixed) and the misplaced labels.

Four racing drivers named after Scottish towns?

EternalOptimist

17th May 2011, 14:05

3 unless the first two socks are joined together in the way most sane people store socks.

will you fck right off.

if i wanted to do a quiz to satisfy you, it would have to come with 200 pages of caveats, 300 volumes of associated assumptions , two county court judgements and a health and fckng safety warning

:rolleyes:

MarillionFan

17th May 2011, 14:07

Four racing drivers named after Scottish towns?

Lewis Hamilton

Stirling Moss

Stig of the Dump

and Ayr Town Senna.

Lewis Hamilton

Stirling Moss

Stig of the Dump

and Ayr Town Senna.

You knew it!

Ayr Town Centre actually.

and;

Johhny Dumfries and Eddie Irvine

MarillionFan

17th May 2011, 14:18

You knew it!

Ayr Town Centre actually.

and;

Johhny Dumfries and Eddie Irvine

(actually I made it up) :emb

will you fck right off.

if i wanted to do a quiz to satisfy you, it would have to come with 200 pages of caveats, 300 volumes of associated assumptions , two county court judgements and a health and fckng safety warning

:rolleyes:

To be honest your quiz does satisfy me. My comments are merely to entertain the braying mass mob surrounding the arena.

TimberWolf

17th May 2011, 14:30

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 ?

:rolleyes:

:spel boy

So as EO hasn't added another question.

What came first the chicken or the egg?

OwlHoot

17th May 2011, 14:33

:spel boy

Huh?! :confused:

So as EO hasn't added another question.

What came first the chicken or the egg?

oo oo I know this, the answer is the egg, I only know this because there was a documentary on Quarks & Co. a few weeks back here on German TV, however, as my German language skills are not 100% then I failed to fully understand the reasoning why.

Ahh here it is Wer war zuerst da - das Huhn oder das Ei? - Quarks & Co - WDR Fernsehen (http://www.wdr.de/tv/quarks/sendungsbeitraege/2003/0422/003_ei.jsp)

and after using the magic of google translate the answer is because eggs have been around much longer than chickens have.

sasguru

17th May 2011, 14:43

duplicate

sasguru

17th May 2011, 14:45

The correct way to approach questions like this is to work out the sample space.

Scenario 1: One of a 2 child family is a girl, probabilty the other is a girl.

Sample space:

BG

GB

GG

the question is asking whats the probability of GG - the answer is 1/3

Scenario 2: The first of a 2 child family is a girl, probability the second is also a girl

Sample space:

GB

GG

Probability of GG is 1/2

Seems simple but not working out the sample space leads you to use your intuition and interestingly human intuition is crap in probabalistic situations.

TimberWolf

17th May 2011, 14:49

The correct way to approach questions like this is to work out the sample space.

Scenario 1: One of a 2 child family is a girl, probabilty the other is a girl.

Sample space:

BG

GB

GG

the question is asking whats the probability of GG - the answer is 1/3

Scenario 2: The first of a 2 child family is a girl, probability the second is also a girl

Sample space:

GB

GG

Probability of GG is 1/2

Incorrect. In your samples more than one is a girl and the question states that *one* is a girl, not at least one.

Pondlife

17th May 2011, 14:50

Cheers Sassy

It made much more sense the 2nd time.

:tongue

EternalOptimist

17th May 2011, 15:00

So as EO hasn't added another question.

What came first the chicken or the egg?

ok, last one for eek

why did the chicken cross the mobius tube ?

:rolleyes:

SimonMac

17th May 2011, 15:01

Cheers Sassy

It made much more sense the 2nd time.

:tongue

3rd time, check post 8 ;)

ok, last one for eek

why did the chicken cross the mobius tube ?

:rolleyes:

to get to the same side.

EternalOptimist

17th May 2011, 15:10

to get to the same side.

correct

OwlHoot

17th May 2011, 15:13

Incorrect. In your samples more than one is a girl and the question states that *one* is a girl, not at least one.

Good point. So the correct solution to the first is actually 0. :rolleyes:

TimberWolf

17th May 2011, 15:17

Good point. So the correct solution to the first is actually 0. :rolleyes:

Yep (assuming only two sexes exist).

sasguru

17th May 2011, 15:52

Incorrect. In your samples more than one is a girl and the question states that *one* is a girl, not at least one.

I can see why you're unemployed.

It's possible the child could be a herm?