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

It is currently 23 Jul 2014, 10:19

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.

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

combination/permutation w/ restricted items

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
Intern
Intern
avatar
Joined: 16 Jul 2006
Posts: 14
Location: New Orleans
Followers: 0

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

combination/permutation w/ restricted items [#permalink] New post 10 Aug 2006, 14:30
I can't seem to answer this one:


Tom is making a CD containing 10 of his favorite songs. He has chosen 2 bues songs and 8 rock songs to be on the cd. The blues songs will be the first and the last songs. How many different orderings of songs on the CD are possible?

thanks.
SVP
SVP
User avatar
Joined: 05 Jul 2006
Posts: 1542
Followers: 5

Kudos [?]: 65 [0], given: 39

 [#permalink] New post 10 Aug 2006, 14:39
I am still struggling my way through this P&C problems.

But i will post my replu either ways it is good to argue about approaches any ways.

8 of the songs in the middle have 8! ways of arranging

The other two songs have two different displays(first ,last) or l(ast and first)

Thus total possibilities are 8!*2

Hope this is right
Senior Manager
Senior Manager
User avatar
Joined: 05 Mar 2006
Posts: 348
Followers: 1

Kudos [?]: 5 [0], given: 0

GMAT Tests User
 [#permalink] New post 10 Aug 2006, 15:56
2*8*7*6*5*4*3*2*1*1 = 80640
Director
Director
User avatar
Joined: 07 Jun 2006
Posts: 513
Followers: 10

Kudos [?]: 72 [0], given: 0

GMAT Tests User
 [#permalink] New post 10 Aug 2006, 16:21
2*8!

2 because 1st and last can be arranged in 2 ways. There are other 8 slots and that forms a permutation of 8! => total is 2*8!

_________________

http://onwardtomba.blogspot.com - MBA, GMAT, INSEAD - the journey.
My 7 GMAT Quant Strategies/Trap
My GMAT Debrief

SVP
SVP
avatar
Joined: 30 Mar 2006
Posts: 1741
Followers: 1

Kudos [?]: 24 [0], given: 0

GMAT Tests User
 [#permalink] New post 10 Aug 2006, 23:22
Clear 2*8!

Blues can be arranged in 2! ways = 2
Rock can be arranged in 8! ways

hence total = 2*8!
GMAT Club Legend
GMAT Club Legend
User avatar
Joined: 07 Jul 2004
Posts: 5097
Location: Singapore
Followers: 16

Kudos [?]: 131 [0], given: 0

GMAT Tests User
 [#permalink] New post 11 Aug 2006, 00:04
Label the blues songs as BA and BB. We're told the blues song make the first and last songs.

So the ordering can be BA _ _ _ _ _ _ _ _ _ BB or BB _ _ _ _ _ _ _ _ _ BA

For the first one, there are 8! ways to order the songs. The second one is the same.

Total = 2(8!)
  [#permalink] 11 Aug 2006, 00:04
    Similar topics Author Replies Last post
Similar
Topics:
3 Experts publish their posts in the topic An item is being sold for $10 each. However, if a customer w actleader 5 31 Oct 2012, 21:39
Combination/Permutation juking77 1 31 May 2011, 12:41
combination/permutation shrive555 2 26 Dec 2010, 18:30
Restrictive vs Non-restrictive clauses dreambeliever 2 12 Dec 2010, 13:40
How to read combination/permutation short hand jeremy02 1 02 Sep 2004, 22:00
Display posts from previous: Sort by

combination/permutation w/ restricted items

  Question banks Downloads My Bookmarks Reviews Important topics  


cron

GMAT Club MBA Forum Home| About| Privacy Policy| Terms and Conditions| GMAT Club Rules| Contact| Sitemap

Powered by phpBB © phpBB Group and phpBB SEO

Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.