Last visit was: 24 Apr 2024, 05:44 It is currently 24 Apr 2024, 05:44
Decision Tracker
My Rewards
New comers' posts
New posts
Unanswered

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.

Go to My Error Log Learn more
Close

Request Expert Reply

Confirm Cancel
PREVIOUS TOPIC
NEXT TOPIC

In how many ways can 4 boys and 4 girls be arranged in a row

Tags :
Find Similar Topics  About  Add a Tag

Show Tags
Hide Tags

User avatar
D
Carcass
Verbal Expert
Joined: 18 Apr 2015
Posts: 28623
Own Kudos [?]: 33105 [2]
Given Kudos: 25173
Send PM
In how many ways can 4 boys and 4 girls be arranged in a row [#permalink] New post   14 May 2019, 00:38
Expert Reply
2
Bookmarks
00:00

Question Stats:

92% (01:04) correct 7% (00:37) wrong based on 52 sessions

Hide Show timer Statistics

In how many ways can 4 boys and 4 girls be arranged in a row such that boys and girls alternate their positions (that is, boy girl)?

(A) 1032

(B) 1152

(C) 1254

(D) 1432

(E) 1564
ShowHide Answer
Official Answer
B
avatar
logann2
Manager
Manager
Joined: 22 Aug 2019
Posts: 96
Own Kudos [?]: 80 [1]
Given Kudos: 0
Send PM
Re: In how many ways can 4 boys and 4 girls be arranged in a row [#permalink] New post   22 Aug 2019, 19:00
1
Carcass wrote:
In how many ways can 4 boys and 4 girls be arranged in a row such that boys and girls alternate their positions (that is, boy girl)?

(A) 1032

(B) 1152

(C) 1254

(D) 1432

(E) 1564


I think I'm finally getting alright at these!

seat 1 we can sit one of 4 boys. so 4 options.
seat 2 we can sit one 4 girls so 4 options.
seat 3 we can sit one of 3 REMAININg boys, so 3 options.
.... (continue the pattern)
and then we flip it the other way. so we multiply it by 2.

2*4!4! = 2 * 4^2 * *3^2 * 2^2 = 2 * 64 * 9 = 2 * 576 = 1152
User avatar
huda
Director
Director
Joined: 22 Jun 2019
Posts: 521
Own Kudos [?]: 635 [1]
Given Kudos: 161
Send PM

Top Member of the Month
Re: In how many ways can 4 boys and 4 girls be arranged in a row [#permalink] New post   29 Nov 2019, 02:53
1
any alternative solution?
avatar
GabSun96
Intern
Intern
Joined: 01 Dec 2019
Posts: 4
Own Kudos [?]: 15 [3]
Given Kudos: 0
Send PM
Re: In how many ways can 4 boys and 4 girls be arranged in a row [#permalink] New post   03 Dec 2019, 11:58
3
Found two well exlpained answers at GMATCLUB.

1st:
First arrange the 4 boys in 4! in a way such B_B_B_B ---> 4!
Then, girls can be arranged in two different ways, G first or B first. So, GBGBGBGB, so girls also in 4!, Or BGBGBGBG.. 4! --> 2*4!
Answer = 4!(4!+4!)=4!*2*4!=24*24*2=576*2=1152

B

2nd:
how many arrangements are there of 4 girls=4!=24, AND of 4 boys=4!=24, AND multiply by two since we could begin seating girls or boys first, so total arrangements is 24*24*2=1152
User avatar
bumpbot
GRE Prep Club Legend
GRE Prep Club Legend
Joined: 07 Jan 2021
Posts: 4415
Own Kudos [?]: 68 [0]
Given Kudos: 0
Send PM
Re: In how many ways can 4 boys and 4 girls be arranged in a row [#permalink] New post   04 Sep 2022, 22:12
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
gmatclubot
[#permalink]
Moderators:
BrushMyQuant
Moderator
1085 posts
VibhuAnurag
GRE Instructor
218 posts

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

Main navigation

Partners

GRE Resources

www.ets.org/gre | About | Terms and Conditions and Privacy Policy | Prep Club for GRE Rules | Contact