Last visit was: 15 Oct 2024, 02:45 It is currently 15 Oct 2024, 02:45

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: 29720
Own Kudos [?]: 35696 [0]
Given Kudos: 25816
Send PM
Retired Moderator
Joined: 07 Jan 2018
Posts: 739
Own Kudos [?]: 1430 [0]
Given Kudos: 93
Send PM
Retired Moderator
Joined: 09 Jun 2020
Posts: 205
Own Kudos [?]: 235 [3]
Given Kudos: 34
GPA: 3.21
Send PM
Verbal Expert
Joined: 18 Apr 2015
Posts: 29720
Own Kudos [?]: 35696 [0]
Given Kudos: 25816
Send PM
Re: A particular natural history museum has three rooms [#permalink]
1
Expert Reply
total ways to arrange 9*8*7= 504
Retired Moderator
Joined: 09 Jun 2020
Posts: 205
Own Kudos [?]: 235 [0]
Given Kudos: 34
GPA: 3.21
Send PM
Re: A particular natural history museum has three rooms [#permalink]
why not 9c3= 84 ways
Verbal Expert
Joined: 18 Apr 2015
Posts: 29720
Own Kudos [?]: 35696 [0]
Given Kudos: 25816
Send PM
Re: A particular natural history museum has three rooms [#permalink]
Expert Reply
Basic principle of counting method

More on our Quant book https://gre.myprepclub.com/forum/gre-quant ... 18819.html

Regards
avatar
Intern
Intern
Joined: 10 Sep 2020
Posts: 26
Own Kudos [?]: 9 [0]
Given Kudos: 0
Send PM
Re: A particular natural history museum has three rooms [#permalink]
1
gajala wrote:
why not 9c3= 84 ways


I also used to struggle with when to just write out ___ X ___ X ___ and when to use the formula. In this case, consider what the formula means "9 choose 3" But we are not really choosing 3. We are choosing 1 per room, or better said, we are choosing any of them for a room and then any of the left ones and then a final time. Perhaps someone else can give an example of this same question reworded so that the formula would be needed? Perhaps if we had 9 fossils, one display room and this one room was going to display 3 fossils at the same time?
Manager
Manager
Joined: 26 Nov 2020
Posts: 110
Own Kudos [?]: 102 [0]
Given Kudos: 31
Send PM
Re: A particular natural history museum has three rooms [#permalink]
If the question was to just select 3, then one could use 9C3 but since this can be arranged differently in the three different rooms, it is 9P3 = 504
User avatar
GRE Prep Club Legend
GRE Prep Club Legend
Joined: 07 Jan 2021
Posts: 4935
Own Kudos [?]: 73 [0]
Given Kudos: 0
Send PM
Re: A particular natural history museum has three rooms [#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
Re: A particular natural history museum has three rooms [#permalink]
Moderators:
GRE Instructor
76 posts
GRE Forum Moderator
37 posts
Moderator
1108 posts
GRE Instructor
222 posts

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