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

It is currently 21 Oct 2014, 04:04

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

If a code word is defined to be a sequence of different

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
Senior Manager
Senior Manager
avatar
Joined: 14 Jul 2005
Posts: 405
Followers: 1

Kudos [?]: 10 [0], given: 0

If a code word is defined to be a sequence of different [#permalink] New post 23 Aug 2006, 19:36
00:00
A
B
C
D
E

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions
If a code word is defined to be a sequence of different letters chosen from the 10 letters A, B, C, D, E, F, G, H, I, and J, what is the ratio of the number of 5-letter code words to the number of 4-letter code words?

A) 5 to 4
B) 3 to 2
C) 2 to 1
D) 5 to 1
E) 6 to 1
Senior Manager
Senior Manager
avatar
Joined: 14 Aug 2006
Posts: 368
Followers: 1

Kudos [?]: 3 [0], given: 0

 [#permalink] New post 23 Aug 2006, 20:01
different sequence of numbers imply that ABCDE is different from EDCBA

so using permutations:

10P5/10P4 = (10!/5! )/ (10!/6!) = 6 to 1

Answer E?
Manager
Manager
avatar
Joined: 20 Mar 2006
Posts: 201
Followers: 1

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

Re: PS - Ratio [#permalink] New post 23 Aug 2006, 20:14
gmatornot wrote:
If a code word is defined to be a sequence of different letters chosen from the 10 letters A, B, C, D, E, F, G, H, I, and J, what is the ratio of the number of 5-letter code words to the number of 4-letter code words?

A) 5 to 4
B) 3 to 2
C) 2 to 1
D) 5 to 1
E) 6 to 1


10c5 = Number of ways of selecting 5 letter code words
= 10*9*8*7*6/5!

10c4 = Number of ways of selecting 4 letter code words
= 10*9*8*7*/4!

@ This point i Divided 10c5/10c4 to get 6/5 which is not one of the answer choices.

So went back and saw that after selecting the 5 digit or 4 digit letter code we could arrange them differently

so Number of ways of selecting 5 letter words and arrangiing them=
10c5 * 5! = 10*9*8*7*6

so Number of ways of selecting 4 letter words and arrangiing them=
10c4 * 4! = 10*9*8*7

So required ratio = 6/1

What is the source of this ?

E

Heman
Manager
Manager
avatar
Joined: 20 Mar 2006
Posts: 201
Followers: 1

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

 [#permalink] New post 23 Aug 2006, 20:17
trivikram wrote:
(10C5*5!)/(10C4*4!) = 3/2

B it is


I believe this calculation comes out to 6/1

Heman
VP
VP
avatar
Joined: 28 Mar 2006
Posts: 1388
Followers: 2

Kudos [?]: 19 [0], given: 0

 [#permalink] New post 24 Aug 2006, 15:22
heman wrote:
trivikram wrote:
(10C5*5!)/(10C4*4!) = 3/2

B it is


I believe this calculation comes out to 6/1

Heman


My bad it is 6:1....

I do this types of mistakes all the time and screw myself up :oops: ....
  [#permalink] 24 Aug 2006, 15:22
    Similar topics Author Replies Last post
Similar
Topics:
If a code word is defined to be a sequence of different goalsnr 3 01 Jun 2008, 12:22
If a code word is defined to be a sequence of different tarek99 4 14 Apr 2008, 12:09
If a code word is defined to be a sequence of different marcodonzelli 3 19 Jan 2008, 05:09
If a code word is defined to be a sequence of different GMATCUBS21 6 23 Jun 2006, 14:35
If a code word is defined to be a sequence of different M8 3 25 Apr 2006, 11:21
Display posts from previous: Sort by

If a code word is defined to be a sequence of different

  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®.