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# How would you do this maths question?

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1. Mr and Mrs Jones have two children. The youngest child is called Helen. What is the probability that Mr and Mrs Jones have 2 daughters?

I have a feeling that I'm overcomplicating what is a rather simple question
2. (Original post by chandmeister)
Mr and Mrs Jones have two children. The youngest child is called Helen. What is the probability that Mr and Mrs Jones have 2 daughters?

I have a feeling that I'm overcomplicating what is a rather simple question
A half. Eliminating the gender of one child leaves room for only 2 options for the other child. Either that, or I am missing complexity here. It's a rather simple question.
3. (Original post by RDKGames)
A half. Eliminating the gender of one child leaves room for only 2 options for the other child. Either that, or I am missing complexity here. It's a rather simple question.
4. wouldn't you do conditional probability

5. (Original post by zainyyyyy)
wouldn't you do conditional probability
6. (Original post by chandmeister)
Mr and Mrs Jones have two children. The youngest child is called Helen. What is the probability that Mr and Mrs Jones have 2 daughters?

I have a feeling that I'm overcomplicating what is a rather simple question
Oh dear. Don't ask that question on TSR, you'll have 75 people rapidly descend on you calling you a cis gendered moron. What if Helen identifies as a donkey with 3.5 legs etc?

SS
7. (Original post by zainyyyyy)
are you unable to answer a simple question or are you up your own arse for going cambridge?
lol wat
8. Hmmmmmm
9. (Original post by Zacken)
(Original post by zainyyyyy)
are you unable to answer a simple question or are you up your own arse for going cambridge?
I think someone's salty
10. Wikipedia lies. I wouldn't trust it mate. Even I could edit it and type in some bs.

him going cambridge doesnt mean he's better than me
(Original post by ValerieKR)
I think someone's salty
12. (Original post by zainyyyyy)

him going cambridge doesnt mean he's better than me
Where did you pull Cambridge from? What does that have to do with anything???
13. (Original post by Kryptonian)
Wikipedia lies. I wouldn't trust it mate. Even I could edit it and type in some bs.
http://math.stackexchange.com/questi...-children-is-a

Better? It's a well known paradox.
14. (Original post by zainyyyyy)

him going cambridge doesnt mean he's better than me
You took personal offence at a simple question - nobody was/is thinking 'haha i'm better than you' and he never even mentioned anything about Cambridge nor valuation of people based on maths abilities.
15. 50% me thinks
16. (Original post by chandmeister)
Mr and Mrs Jones have two children. The youngest child is called Helen. What is the probability that Mr and Mrs Jones have 2 daughters?

I have a feeling that I'm overcomplicating what is a rather simple question
B = Boy G = Girl
BB = 0.25
BG | GB = 0.50
GG = 0.25
17. (Original post by skkrrr)
B = Boy G = Girl
BB = 0.25
BG | GB = 0.50
GG = 0.25
See above- you are not incorporating useful information that tells you BB = 0
18. (Original post by mik1a)
See above- you are not incorporating useful information that tells you BB = 0
What do you mean? Nothing in the question tells you the gender of 'Helen' or there is no boys. So you have to assume Helen can be male or female meaning what I said above is correct in that sense?
19. so was i right?
20. (Original post by skkrrr)
so was i right?
No.

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