Find all School-related info fast with the new School-Specific MBA Forum

 It is currently 14 Sep 2014, 20:29

### GMAT Club Daily Prep

#### Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# There is a family with two children. One is a boy, what is

Author Message
TAGS:
Director
Joined: 03 Jul 2003
Posts: 656
Followers: 2

Kudos [?]: 14 [0], given: 0

There is a family with two children. One is a boy, what is [#permalink]  14 Feb 2004, 23:35
There is a family with two children. One is a boy, what is the
probability that the other is a girl?
GMAT Club Legend
Joined: 15 Dec 2003
Posts: 4318
Followers: 22

Kudos [?]: 161 [0], given: 0

1/2 if the fact that the first kid being a boy is independent of the second kid being a girl
1/4 if the question is about the probability of having first kid a boy and second kid a girl
_________________

Best Regards,

Paul

SVP
Joined: 30 Oct 2003
Posts: 1798
Location: NewJersey USA
Followers: 4

Kudos [?]: 34 [0], given: 0

I stand by Paul on this one.

Hi Paul,

By any chance r u registered at TestMagic as Paul78 ?

Anand.
Director
Joined: 03 Jul 2003
Posts: 656
Followers: 2

Kudos [?]: 14 [0], given: 0

Paul wrote:
1/2 if the fact that the first kid being a boy is independent of the second kid being a girl
1/4 if the question is about the probability of having first kid a boy and second kid a girl

Sex of any baby is indepedent of its siblings.
Question stem does not say the first baby is boy.
All it says is one is boy.
SVP
Joined: 30 Oct 2003
Posts: 1798
Location: NewJersey USA
Followers: 4

Kudos [?]: 34 [0], given: 0

Then what we have is

BG GB GG BB
so dsired events are BG and GB total events are 4
2/4 = 1/2
Director
Joined: 03 Jul 2003
Posts: 656
Followers: 2

Kudos [?]: 14 [0], given: 0

But, here is my explanation.

Total possibilities = BB, GG, BG, GB
One(Atleast) is BOY = BB, BG, GB
Another is Girl,given than other is BOY = BG , GB

P = 2/3.

As i said before, I don't have official answer!
GMAT Club Legend
Joined: 15 Dec 2003
Posts: 4318
Followers: 22

Kudos [?]: 161 [0], given: 0

interesting reasoning kpadma. Indeed, you would then have to remove GG to get 2/3. I think it should be right then. Anandnk, yes i'm paul78 on testmagic. Put the same signature so that you could recognize me... you stalker!
_________________

Best Regards,

Paul

GMAT Instructor
Joined: 07 Jul 2003
Posts: 771
Location: New York NY 10024
Schools: Haas, MFE; Anderson, MBA; USC, MSEE
Followers: 9

Kudos [?]: 30 [0], given: 0

But, here is my explanation.

Total possibilities = BB, GG, BG, GB
One(Atleast) is BOY = BB, BG, GB
Another is Girl,given than other is BOY = BG , GB

P = 2/3.

As i said before, I don't have official answer!

The question should be worded "at least one is a boy" and in that case, 2/3 is the answer. Trust me.

However, as worded, the question states: "ONE is a boy". hence the other child MUST be a girl. If the other was a boy, then the statement "ONE is a boy" would not be true -- because in that case TWO of them are boys!

Of course, this is an oversight and the GMAT would not be so ambiguous.

_________________

Best,

AkamaiBrah
Former Senior Instructor, Manhattan GMAT and VeritasPrep
Vice President, Midtown NYC Investment Bank, Structured Finance IT
MFE, Haas School of Business, UC Berkeley, Class of 2005
MBA, Anderson School of Management, UCLA, Class of 1993

Director
Joined: 03 Jul 2003
Posts: 656
Followers: 2

Kudos [?]: 14 [0], given: 0

AkamaiBrah wrote:
The question should be worded "at least one is a boy" and in that case, 2/3 is the answer. Trust me.

However, as worded, the question states: "ONE is a boy". hence the other child MUST be a girl. If the other was a boy, then the statement "ONE is a boy" would not be true -- because in that case TWO of them are boys!

Of course, this is an oversight and the GMAT would not be so ambiguous.

Yes, Adding "atleast" makes the question clearer.
Thanks Akamai!
Similar topics Replies Last post
Similar
Topics:
1 The Coen family consists of a father, a mother, two children 5 30 May 2012, 21:13
3 What is the probability for a family with three children to 4 06 Feb 2011, 01:20
4 A family consisting of one mother, one father, two daughters 6 01 Sep 2008, 21:30
A family consisting of one mother, one father, two daughters 9 22 Nov 2006, 12:50
What is the probability for a family with three children to 6 17 Apr 2006, 05:45
Display posts from previous: Sort by