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.

It appears that you are browsing the GMAT Club forum unregistered!

Signing up is free, quick, and confidential.
Join other 500,000 members and get the full benefits of GMAT Club

Registration gives you:

Tests

Take 11 tests and quizzes from GMAT Club and leading GMAT prep companies such as Manhattan GMAT,
Knewton, and others. All are free for GMAT Club members.

Applicant Stats

View detailed applicant stats such as GPA, GMAT score, work experience, location, application
status, and more

Books/Downloads

Download thousands of study notes,
question collections, GMAT Club’s
Grammar and Math books.
All are free!

Thank you for using the timer!
We noticed you are actually not timing your practice. Click the START button first next time you use the timer.
There are many benefits to timing your practice, including:

5 girls and 3 boys are arranged randomly in a row. Find the probability that:

1) there is one boy on each end. 2) There is one girl on each end.

A. 3/28 & 5/14 B. 5/28 & 3/14 C. 5/14 & 3/28 D. 3/28 & 1/14 E. 1/28 & 5/14

Total # of arrangements is 8!;

1. The # of arrangements where there is one boy on each end is \(C^2_3*2*6!\), where \(C^2_3\) is # of ways to select which 2 boys will be on that positions, *2 # of way to arrange them on that position (A------B and B------A) and 6! is # of arrangements of 6 people left;

\(P=\frac{C^2_3*2*6!}{8!}=\frac{3}{28}\).

2. The # of arrangements where there is one girl on each end is \(C^2_5*2*7!\), where \(C^2_5\) is # of ways to select which 2 girls will be on that positions, *2 # of way to arrange them on that position (A------B and B------A) and 6! is # of arrangements of 6 people left;

Re: 5 girls and 3 boys are arranged randomly in a row [#permalink]

Show Tags

06 Mar 2013, 19:28

1

This post received KUDOS

Hi Bunel, firstly I would like to thank you for all the help you've given to the forum! You have been nothing but superb!

I have a question on this though, would it be possible also to solve the question as below? I had solved it like this initially and I'm not sure now if I have some mistakes in my fundamental theory. It would be great if you could help clarify. Thank you!

Hi Bunel, firstly I would like to thank you for all the help you've given to the forum! You have been nothing but superb!

I have a question on this though, would it be possible also to solve the question as below? I had solved it like this initially and I'm not sure now if I have some mistakes in my fundamental theory. It would be great if you could help clarify. Thank you!

1) [m]P=(P^2_3*6!)/8!

2) [m]P=(P^2_5*6!)/8!

Yes, your approach is fine: 3P2=3C2*2! and 5P2=5C2*2!.

Re: 5 girls and 3 boys are arranged randomly in a row [#permalink]

Show Tags

19 Jul 2014, 09:14

Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________

Re: 5 girls and 3 boys are arranged randomly in a row [#permalink]

Show Tags

24 Aug 2015, 12:08

Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________

Re: 5 girls and 3 boys are arranged randomly in a row [#permalink]

Show Tags

10 Sep 2016, 15:34

Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________

Re: 5 girls and 3 boys are arranged randomly in a row [#permalink]

Show Tags

16 Sep 2017, 23:31

Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________

Version 8.1 of the WordPress for Android app is now available, with some great enhancements to publishing: background media uploading. Adding images to a post or page? Now...

“Keep your head down, and work hard. Don’t attract any attention. You should be grateful to be here.” Why do we keep quiet? Being an immigrant is a constant...

“Keep your head down, and work hard. Don’t attract any attention. You should be grateful to be here.” Why do we keep quiet? Being an immigrant is a constant...