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

It is currently 24 Jul 2014, 12:05

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

Let each different arrangement of all the letters of DELETED

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
Director
Director
avatar
Joined: 21 Aug 2005
Posts: 795
Followers: 2

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

GMAT Tests User
Let each different arrangement of all the letters of DELETED [#permalink] New post 19 Oct 2005, 16:12
00:00
A
B
C
D
E

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions
Let each different arrangement of all the letters of DELETED be called a word.
(a) How many words are possible?
(b) In how many of these words will the D's be separated?
VP
VP
avatar
Joined: 22 Aug 2005
Posts: 1128
Location: CA
Followers: 1

Kudos [?]: 23 [0], given: 0

GMAT Tests User
 [#permalink] New post 19 Oct 2005, 16:37
(a) total words = 7! / 3! * 2! as there are 3 Es and 2 Ds
= 420

(b) total number of words where both Ds are TOGETHER - count 2 Ds as 1:
number of words = 6!/3! = 120
number of words where Ds are not together = 420 - 120 = 300
Manager
Manager
avatar
Joined: 04 May 2005
Posts: 133
Location: Chicago
Followers: 1

Kudos [?]: 1 [0], given: 0

 [#permalink] New post 19 Oct 2005, 16:41
A. 7!/(3!2!). 7=total amount of letters, must divide repeated elements. 3=total number of repeating letter E. 2= amount of repeating letter D


B. I will try (the amount above)-(the amount of ways in which D will not be separated). I basically take DD as one letter. However, I do not know how to set it up. Help anyone?
_________________

Christopher Wilson

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 19 Oct 2005, 18:25
(A) 7!/3!2! (Divide by 3! as we have 3 E's and 2! as we had 2 D's)-> 420

(B) Treat the 2 D's as one entity, then we will have 6!/3! = 120 words where the two D's are together. So # of words where D are aparts = 420-120 = 300
Director
Director
avatar
Joined: 21 Aug 2005
Posts: 795
Followers: 2

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

GMAT Tests User
 [#permalink] New post 19 Oct 2005, 19:53
OA is 420 and 300.

I am weak in this area. Can someone explain more in detail how we get the 6! in (b)? I am just not able to visualize :cry:

Also, Titelist, do you hear me?!!! Need some 'graphical' help!!
SVP
SVP
User avatar
Joined: 05 Apr 2005
Posts: 1736
Followers: 3

Kudos [?]: 29 [0], given: 0

GMAT Tests User
 [#permalink] New post 19 Oct 2005, 20:14
gsr wrote:
OA is 420 and 300.
I am weak in this area. Can someone explain more in detail how we get the 6! in (b)? I am just not able to visualize :cry:
Also, Titelist, do you hear me?!!! Need some 'graphical' help!!

total possiblities = 7!/(3! 2!) = 420
total possibilities with D's togather = 6(5!)/3! = 6!/3! = 120
so poss D's seperate = 420 - 120 = 300

in the following ways, we can arrange D's togather so that we get 120:

1st place = DD----- = 2(5!/3!2!) = 5!/3! = 20
2nd place = -DD---- = 5!/3! = 20
3rd place = --DD--- = 5!/3! = 20
4th place = ---DD-- = 5!/3! = 20
5th place = ----DD- = 5!/3! = 20
6th place = -----DD = 5!/3! = 20

total = 120

i am not sure whether it helps or not... 8-)
Director
Director
avatar
Joined: 21 Aug 2005
Posts: 795
Followers: 2

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

GMAT Tests User
 [#permalink] New post 19 Oct 2005, 20:19
6(5!)/3! - This was the missing link!!!

Thanks Himalaya!!
--------------

:wall

Left side - 'me'
Right side - 'probability'
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 19 Oct 2005, 20:22
gsr wrote:
OA is 420 and 300.

I am weak in this area. Can someone explain more in detail how we get the 6! in (b)? I am just not able to visualize :cry:

Also, Titelist, do you hear me?!!! Need some 'graphical' help!!


There are 7 letters, but because we treated the two D's as one entity, it becomes 6 letters now. (We treat D as an entity to calculate number of words where the two D's will be together). Since we now have 6 spaces to fill, so it becomes 6!
SVP
SVP
User avatar
Joined: 05 Apr 2005
Posts: 1736
Followers: 3

Kudos [?]: 29 [0], given: 0

GMAT Tests User
 [#permalink] New post 19 Oct 2005, 20:45
gsr wrote:
6(5!)/3! - This was the missing link!!!
Left side - 'me'
Right side - 'probability'


precisely the above expression is = 2(6)(5!)/(3!2!) = 6!/3! = 120
  [#permalink] 19 Oct 2005, 20:45
    Similar topics Author Replies Last post
Similar
Topics:
5 Experts publish their posts in the topic In the multiplication above, each letter stands for a differ irda 4 19 Oct 2013, 13:25
2 Experts publish their posts in the topic How many different arrangements of letters are possible if rxs0005 4 27 Nov 2010, 06:49
1 Experts publish their posts in the topic arrangment of letters abeer16 9 14 Oct 2010, 07:14
Experts publish their posts in the topic Let each different arrangement of all the letters of DELETED amitjash 1 20 May 2010, 22:32
Let x,y,z be three different positive integers each less faifai0714 3 13 Oct 2006, 17:55
Display posts from previous: Sort by

Let each different arrangement of all the letters of DELETED

  Question banks Downloads My Bookmarks Reviews Important topics  


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®.