Last visit was: 25 Apr 2024, 14:28 It is currently 25 Apr 2024, 14:28

Close

GRE Prep 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 GRE 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.

Close

Request Expert Reply

Confirm Cancel
Verbal Expert
Joined: 18 Apr 2015
Posts: 28635
Own Kudos [?]: 33119 [1]
Given Kudos: 25175
Send PM
User avatar
Director
Director
Joined: 22 Jun 2019
Posts: 521
Own Kudos [?]: 637 [0]
Given Kudos: 161
Send PM
Manager
Manager
Joined: 05 Aug 2020
Posts: 101
Own Kudos [?]: 229 [0]
Given Kudos: 14
Send PM
Retired Moderator
Joined: 10 Apr 2015
Posts: 6218
Own Kudos [?]: 11682 [0]
Given Kudos: 136
Send PM
Re: How many different four-letter words can be formed (the wor [#permalink]
grenico wrote:
Can you please explain how they are not important?

To me, G1 G2 R1 R2 are the same, so we would get repetition with GGRR, GRGR, GG_R, and G_RR


I believe you're saying the same thing as huda.

For example, I believe you're both saying G1 and G2 are indistinguishable (identical). The same applies to R1 and R2
avatar
Manager
Manager
Joined: 22 Jan 2020
Posts: 120
Own Kudos [?]: 228 [1]
Given Kudos: 10
Send PM
Re: How many different four-letter words can be formed (the wor [#permalink]
1
_ _ _ _

Experiment1: Choose a G for the first slot
Experiment2: Choose an R for the last slot
Experiment3: Choose a letter from the remaining for the third slot
Experiment4: Choose a letter from the remaining for the fourth slot

We have 2 G's and 2 R's

Total Outcome in Experiment1: 2
Total Outcome in Experiment2: 2
Total Outcome in Experiment3: 8
Total Outcome in Experiment4: 7

We use principle of counting

Total outcomes= 2*2*8*7

But we need to divide by (2*2), because we can't distinguish the two G's or R's if the words contain two of them.

Total outcomes= (2*2*8*7)/(2*2)= 8*7

8P2= 8!/(8-2)!= 8!/6!= 8*7

Final Answer: A
avatar
Manager
Manager
Joined: 19 Jan 2020
Posts: 56
Own Kudos [?]: 66 [1]
Given Kudos: 0
Send PM
Re: How many different four-letter words can be formed (the wor [#permalink]
1
A way to do it is:

G _ _ R

With 1 G and 1 R already used, you have one of the 8 letters that can fill the first blank and one of 7 letters can fill the second blank.

So, G 8 7 R. So you can arrange the letters in 8*7 ways.

8P2 = 8*7 = 56.
User avatar
GRE Prep Club Legend
GRE Prep Club Legend
Joined: 07 Jan 2021
Posts: 4420
Own Kudos [?]: 68 [0]
Given Kudos: 0
Send PM
Re: How many different four-letter words can be formed (the wor [#permalink]
Hello from the GRE Prep Club BumpBot!

Thanks to another GRE Prep Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
Prep Club for GRE Bot
[#permalink]
Moderators:
Moderator
1085 posts
GRE Instructor
218 posts

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