BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

Permutations-word arrangement

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
User avatar
Master | Next Rank: 500 Posts
Posts: 212
Joined: Sat Dec 01, 2007 4:19 pm
Thanked: 5 times

Permutations-word arrangement

by vscid » Sat Feb 27, 2010 6:57 am
How many different words can be made from the word REVIEW, such that W is always before R?

(Sorry I don't have options)
The GMAT is indeed adaptable. Whenever I answer RC, it proficiently 'adapts' itself to mark my 'right' answer 'wrong'.
Top
Source: — Problem Solving |
Junior | Next Rank: 30 Posts
Posts: 26
Joined: Fri Feb 26, 2010 8:56 pm
Thanked: 2 times

by seanceserene » Sat Feb 27, 2010 7:19 am
a total of 6!=6*5*4*3*2*1=720 different words can be made from these six letters
the possibilty that W is before R and R is before W is the same
thus we have 720*50%=360
it is not an "alice in wonderland". it is real! i am going to freak GMAT out!
Top
Senior | Next Rank: 100 Posts
Posts: 60
Joined: Wed Jan 07, 2009 1:56 pm
Thanked: 12 times
GMAT Score:750

by arzanr » Sat Feb 27, 2010 7:26 am
seanceserene wrote:a total of 6!=6*5*4*3*2*1=720 different words can be made from these six letters
the possibilty that W is before R and R is before W is the same
thus we have 720*50%=360
Good call that we can simply divide the total by two since the number with R before W and vice versa would be the same. However, we also need to account for the fact that the word has two Es. Therefore, you need to take 6!/2! in the overall total. Final answer should be 180.

Note: E.g. If you take 6! instead of 6!/2! you are counting EERVIW twice
Top
Junior | Next Rank: 30 Posts
Posts: 26
Joined: Fri Feb 26, 2010 8:56 pm
Thanked: 2 times

by seanceserene » Sat Feb 27, 2010 7:47 am
arzanr wrote:
seanceserene wrote:a total of 6!=6*5*4*3*2*1=720 different words can be made from these six letters
the possibilty that W is before R and R is before W is the same
thus we have 720*50%=360
Good call that we can simply divide the total by two since the number with R before W and vice versa would be the same. However, we also need to account for the fact that the word has two Es. Therefore, you need to take 6!/2! in the overall total. Final answer should be 180.

Note: E.g. If you take 6! instead of 6!/2! you are counting EERVIW twice
Great! thank you for pointing out my mistake!!
carelessness is my greatest enemy in Math
hope that i don't make the same mistake next time
it is not an "alice in wonderland". it is real! i am going to freak GMAT out!
Top
User avatar
Legendary Member
Posts: 748
Joined: Sun Jan 31, 2010 7:54 am
Thanked: 46 times
Followed by:3 members

by outreach » Sat Feb 27, 2010 8:01 am
the word REVIEW can be grouped in 6! ways=6*5*4*3*2*1= 720
since two E present in the word, divide eq 720 by 2!=> 360
since W is always before R divide 360 by 2!=180
-------------------------------------
--------------------------------------
General blog
https://amarnaik.wordpress.com
MBA blog
https://amarrnaik.blocked/
Top
Post new topic Post Reply
• Page 1 of 1