Last visit was: 26 Apr 2026, 17:08 It is currently 26 Apr 2026, 17:08
Close
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
Your Progress

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
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
Close
Request Expert Reply
Confirm Cancel
User avatar
KarishmaB
Joined: 16 Oct 2010
Last visit: 26 Apr 2026
Posts: 16,441
Own Kudos:
79,419
 [1]
Given Kudos: 485
Location: Pune, India
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 16,441
Kudos: 79,419
 [1]
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post
User avatar
gmatpro15
Joined: 09 Aug 2022
Last visit: 12 Aug 2024
Posts: 80
Own Kudos:
Given Kudos: 48
Location: India
Concentration: General Management, Leadership
GPA: 4
WE:Design (Real Estate)
Posts: 80
Kudos: 25
Kudos
Add Kudos
Bookmarks
Bookmark this Post
User avatar
MBAHOUSE
User avatar
MBA House Admissions Consultant
Joined: 26 May 2022
Last visit: 23 Apr 2024
Posts: 337
Own Kudos:
Expert
Expert reply
Posts: 337
Kudos: 98
Kudos
Add Kudos
Bookmarks
Bookmark this Post
User avatar
DanTheGMATMan
Joined: 02 Oct 2015
Last visit: 23 Apr 2026
Posts: 380
Own Kudos:
Given Kudos: 9
Expert
Expert reply
Posts: 380
Kudos: 267
Kudos
Add Kudos
Bookmarks
Bookmark this Post
­Sorry for sound quality hah. Set up one order of 4 boys and 2 girls (each has 1/2 probability). Multiply by the number of different orders:

User avatar
AA155
Joined: 18 Apr 2025
Last visit: 26 Apr 2026
Posts: 26
Own Kudos:
Given Kudos: 3
Location: India
GPA: 6
Products:
Kudos
Add Kudos
Bookmarks
Bookmark this Post
can we also do (1/2)^6 x 6!/4!x2! ans comes out to be the same

here the chance of a child being boy or girl is 1/2 and since there are 6 we are looking for BBBBGG and thus (1/2)^6 but to avoid arrangement issues we can multiply by 6!/4!x2!
Bunuel
The probability that a family with 6 children has exactly four boys is:

A. 1/3
B. 1/64
C. 15/64
D. 3/8
E. none of the above

NOTE: If the probability of a certain event is \(p\) (\(\frac{1}{2}\) in our case), then the probability of it occurring \(k\) times (4 times in our case) in \(n\)-time (6 in our case) sequence is:

\(P = C^k_n*p^k*(1-p)^{n-k}\)

\(P = C^k_n*p^k*(1-p)^{n-k}= C^4_6*(\frac{1}{2})^4*(1-\frac{1}{2})^{6-4}= C^4_6*(\frac{1}{2})^4*(\frac{1}{2})^{2}=\frac{6!}{4!2!}*\frac{1}{2^6}=\frac{15}{64}\)


Consider this:

We are looking for the case BBBBGG, probability of each B or G is \(\frac{1}{2}\), hence \(\frac{1}{2^6}\). But BBBBGG can occur (these letters can be arranged) in \(\frac{6!}{4!2!}\) # of ways. So, the total probability would be \(\frac{6!}{4!2!}*\frac{1}{2^6}=\frac{15}{64}\).

Answer: C.
User avatar
PocusFocus
User avatar
IESE School Moderator
Joined: 27 Nov 2023
Last visit: 20 Apr 2026
Posts: 347
Own Kudos:
Given Kudos: 472
Location: Peru
GMAT Focus 1: 575 Q86 V79 DI70
GMAT Focus 2: 525 Q82 V77 DI69
GMAT Focus 3: 575 Q83 V76 DI77
GMAT Focus 4: 625 Q84 V78 DI81
GMAT 1: 500 Q42 V18
WE:Corporate Finance (Manufacturing)
GMAT Focus 4: 625 Q84 V78 DI81
GMAT 1: 500 Q42 V18
Posts: 347
Kudos: 59
Kudos
Add Kudos
Bookmarks
Bookmark this Post
This is an unpopular approach but I will disagree with your solutions, I would have marked E, a here is why:
The statement says a family with 6 children it could be 0B6G, 1B5G, ..., 6B0G, so 7 cases... nobody mentions anything about the order in which this family have the children... so the probability would be 1/7
GMATMadeeasy
The probability that a family with 6 children has exactly four boys is:

A. 1/3
B. 1/64
C. 15/64
D. 3/8
E. none of the above
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 26 Apr 2026
Posts: 109,910
Own Kudos:
Given Kudos: 105,897
Products:
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 109,910
Kudos: 811,439
Kudos
Add Kudos
Bookmarks
Bookmark this Post
PocusFocus
This is an unpopular approach but I will disagree with your solutions, I would have marked E, a here is why:
The statement says a family with 6 children it could be 0B6G, 1B5G, ..., 6B0G, so 7 cases... nobody mentions anything about the order in which this family have the children... so the probability would be 1/7


You are misunderstanding the question. It asks about the probability of having 4 boys and 2 girls. Each of the correct solutions in the thread considers the order of BBBBGG. Please review the solutions again.
   1   2 
Moderators:
Math Expert
109910 posts
Tuck School Moderator
852 posts