GMAT Question of the Day - Daily to your Mailbox; hard ones only

 It is currently 18 Jul 2018, 22:17

### 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

# Combinatorics

Author Message
Intern
Joined: 13 May 2009
Posts: 19

### Show Tags

04 Aug 2009, 13:38
00:00

Difficulty:

(N/A)

Question Stats:

100% (00:28) correct 0% (00:00) wrong based on 0 sessions

### HideShow timer Statistics

Three dwarves and three elves sit down in a row of six chairs. If no dwarf will sit next to other dwarf and no elf will sit to another elf, in how many different ways can the elves and dwarves sit?

--== Message from GMAT Club Team ==--

This is not a quality discussion. It has been retired.

If you would like to discuss this question please re-post it in the respective forum. Thank you!

To review the GMAT Club's Forums Posting Guidelines, please follow these links: Quantitative | Verbal Please note - we may remove posts that do not follow our posting guidelines. Thank you.
CEO
Joined: 17 Nov 2007
Posts: 3484
Concentration: Entrepreneurship, Other
Schools: Chicago (Booth) - Class of 2011
GMAT 1: 750 Q50 V40

### Show Tags

04 Aug 2009, 13:46
1) There is 2 possible options how dwarves and elves could be placed: dedede or ededed

2) There is $$P_3^3$$ options for 3 dwarves/elves for choosing 3 chairs

3) Finally, $$2*P_3^3*P_3^3 = 2*3!*3! = 72$$
_________________

HOT! GMAT TOOLKIT 2 (iOS) / GMAT TOOLKIT (Android) - The OFFICIAL GMAT CLUB PREP APP, a must-have app especially if you aim at 700+ | PrepGame

Intern
Joined: 13 May 2009
Posts: 19

### Show Tags

04 Aug 2009, 14:00
Two Options :-

1.) DEDEDE

2.) EDEDED

Persons Choices Seat Assigned

Dwarf A 6 Choices(1,2,3,4,5,6) #1
Dwarf B 2 Choices(3,5) #3
Dwarf C 1 Choice(5) #5
ELF A 3 Choices(2,4,6) #2
ELF B 2 Choices(4,6) #4
ELF C 1 Choice(6) #6

Final product 6*2*1*3*2*1 =72

If the same process is followed for option 2 we will get the same result of 72. In that case the answer should be 72+72?? Correct me if i am wrong!
Senior Manager
Joined: 17 Jul 2009
Posts: 259
Concentration: Nonprofit, Strategy
GPA: 3.42
WE: Engineering (Computer Hardware)

### Show Tags

04 Aug 2009, 15:01
lbsgmat wrote:
Two Options :-

1.) DEDEDE

2.) EDEDED

Persons Choices Seat Assigned

Dwarf A 6 Choices(1,2,3,4,5,6) #1
Dwarf B 2 Choices(3,5) #3
Dwarf C 1 Choice(5) #5
ELF A 3 Choices(2,4,6) #2
ELF B 2 Choices(4,6) #4
ELF C 1 Choice(6) #6

Final product 6*2*1*3*2*1 =72

If the same process is followed for option 2 we will get the same result of 72. In that case the answer should be 72+72?? Correct me if i am wrong!

because your Dwarf A could choose among all 6 seats, so that's including both option 1 and 2 there
Manager
Joined: 18 Jul 2009
Posts: 166
Location: India
Schools: South Asian B-schools

### Show Tags

06 Aug 2009, 09:41
dedede or ededed

Hence 3! x 3! x 2 = 72

--== Message from GMAT Club Team ==--

This is not a quality discussion. It has been retired.

If you would like to discuss this question please re-post it in the respective forum. Thank you!

To review the GMAT Club's Forums Posting Guidelines, please follow these links: Quantitative | Verbal Please note - we may remove posts that do not follow our posting guidelines. Thank you.

_________________

Bhushan S.
If you like my post....Consider it for Kudos

Re: Combinatorics   [#permalink] 06 Aug 2009, 09:41
Display posts from previous: Sort by

# Combinatorics

Moderators: chetan2u, KarishmaB, Bunuel, niks18

# Events & Promotions

 Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne 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®.