• Economist Test Prep
    Free Trial & Practice Exam
    BEAT THE GMAT EXCLUSIVE

    Available with Beat the GMAT members only code

    MORE DETAILS
    Economist Test Prep
  • Magoosh
    Magoosh
    Study with Magoosh GMAT prep

    Available with Beat the GMAT members only code

    MORE DETAILS
    Magoosh
  • Varsity Tutors
    Award-winning private GMAT tutoring
    Register now and save up to $200

    Available with Beat the GMAT members only code

    MORE DETAILS
    Varsity Tutors
  • Target Test Prep
    5-Day Free Trial
    5-day free, full-access trial TTP Quant

    Available with Beat the GMAT members only code

    MORE DETAILS
    Target Test Prep
  • Kaplan Test Prep
    Free Practice Test & Review
    How would you score if you took the GMAT

    Available with Beat the GMAT members only code

    MORE DETAILS
    Kaplan Test Prep
  • PrepScholar GMAT
    5 Day FREE Trial
    Study Smarter, Not Harder

    Available with Beat the GMAT members only code

    MORE DETAILS
    PrepScholar GMAT
  • EMPOWERgmat Slider
    1 Hour Free
    BEAT THE GMAT EXCLUSIVE

    Available with Beat the GMAT members only code

    MORE DETAILS
    EMPOWERgmat Slider
  • The Princeton Review
    FREE GMAT Exam
    Know how you'd score today for $0

    Available with Beat the GMAT members only code

    MORE DETAILS
    The Princeton Review
  • e-gmat Exclusive Offer
    Get 300+ Practice Questions
    25 Video lessons and 6 Webinars for FREE

    Available with Beat the GMAT members only code

    MORE DETAILS
    e-gmat Exclusive Offer
  • Veritas Prep
    Free Veritas GMAT Class
    Experience Lesson 1 Live Free

    Available with Beat the GMAT members only code

    MORE DETAILS
    Veritas Prep

At a circular table for eight will sit two children

This topic has 1 member reply

At a circular table for eight will sit two children

Post
At a circular table for eight will sit two children, their two parents, and the two parents of each of the children's parents, eight people in total. The children will sit together, the children's two parents will sit next to the children, one on either side of the two children, and the parents of each of the children's parents will sit next to each other beside the person who is their child. Given the restrictions, in how many ways can the people be arranged around the table.

(A) 8
(B) 16
(C) 64
(D) 96
(E) 1440

The OA is the option B.

Experts, how can I solve this question? Is there an easy way? Can you help me? Thanks in advanced.

  • +1 Upvote Post
  • Quote
  • Flag

Top Member

Top Reply
Post
M7MBA wrote:
At a circular table for eight will sit two children, their two parents, and the two parents of each of the children's parents, eight people in total. The children will sit together, the children's two parents will sit next to the children, one on either side of the two children, and the parents of each of the children's parents will sit next to each other beside the person who is their child. Given the restrictions, in how many ways can the people be arranged around the table.

(A) 8
(B) 16
(C) 64
(D) 96
(E) 1440

The OA is the option B.

Experts, how can I solve this question? Is there an easy way? Can you help me? Thanks in advanced.
Pick the abbreviations of your choice to represent each person and write down according to question, so:

C1 and C2 children
P1 and P2 parents
G11, G12 parents of P1
G21 and G22 parents of P2

So, one ordering is as follows: G11 G12 P1 C1 C2 P2 G21 G22

Now, from the wording the GGPs are a package deal, wherever P moves to so do the G's.

Start with the two children, they can be arranged two ways: C1 C2 or C2 C1 so 2 ways

Within each GGP package the grandparents can be arranged two ways so 2 ways for each package means 2 x 2 = 4 ways

Finally the GGP packages can be swapped to either side, so 2 ways

Totalling: 2x4x2 = 16, B

  • +1 Upvote Post
  • Quote
  • Flag

Top First Responders*

1 Jay@ManhattanReview 81 first replies
2 Brent@GMATPrepNow 67 first replies
3 fskilnik 54 first replies
4 GMATGuruNY 37 first replies
5 Rich.C@EMPOWERgma... 13 first replies
* Only counts replies to topics started in last 30 days
See More Top Beat The GMAT Members

Most Active Experts

1 image description fskilnik

GMAT Teacher

201 posts
2 image description Brent@GMATPrepNow

GMAT Prep Now Teacher

155 posts
3 image description Scott@TargetTestPrep

Target Test Prep

105 posts
4 image description Jay@ManhattanReview

Manhattan Review

97 posts
5 image description GMATGuruNY

The Princeton Review Teacher

91 posts
See More Top Beat The GMAT Experts