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 GMAT 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.

Thank you for using the timer!
We noticed you are actually not timing your practice. Click the START button first next time you use the timer.
There are many benefits to timing your practice, including:

Two couples and one single person are seated at random in a [#permalink]
19 Dec 2007, 18:05

00:00

A

B

C

D

E

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct
0% (00:00) wrong based on 0 sessions

Two couples and one single person are seated at random in a row of five chairs. What is the probability that neither of the couples sit together in adjacent chairs ?

Re: PS couple seating [#permalink]
19 Dec 2007, 21:13

young_gun wrote:

Two couples and one single person are seated at random in a row of five chairs. What is the probability that neither of the couples sit together in adjacent chairs ?

a. 1/5 b. 1/4 c. 3/8 d. 2/5 e. 1/2

AB is the first couple XY is the second couple

S is the sinlge person

Probability that neither sit together =1- probability that they do sit together.

First 5! is the total possiblities

then SABXY 4!. but we must count ABXYS so 4!*2

48/120 = 2/5

Something doesnt seem right with this answer...

shouldnt I be getting 3/5? since 48/120 is the probability that they do sit together?

Could you please explain what is 123??? What are these numbers signifying? What do you mean by mirror symmetry?
It'd be so nice of you, if could explain this a bit more.
-Thanks