It is currently 20 Feb 2018, 09:49

# Live Now:

Ace the Booth Interview - Live on YouTube

### GMAT 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

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

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# A group of 5 students bought movie tickets in one row next

Author Message
TAGS:

### Hide Tags

Intern
Joined: 16 Jan 2013
Posts: 30
Concentration: Finance, Entrepreneurship
GMAT Date: 08-25-2013
A group of 5 students bought movie tickets in one row next [#permalink]

### Show Tags

12 Aug 2013, 01:40
4
This post was
BOOKMARKED
00:00

Difficulty:

55% (hard)

Question Stats:

63% (01:06) correct 37% (01:42) wrong based on 194 sessions

### HideShow timer Statistics

A group of 5 students bought movie tickets in one row next to each other. If Bob and Lisa are in this group, what is the probability that Bob and Lisa will each sit next to only one of the four other students from the group?

(A) 5%
(B) 10%
(C) 15%
(D) 20%
(E) 25%

Can somebody plz clarify that the answer to this prob is 4!*2 which I am getting, but the answer in the book is given something else.
[Reveal] Spoiler: OA

Last edited by Bunuel on 12 Aug 2013, 02:05, edited 2 times in total.
Renamed the topic, edited the question and added the OA.
Math Expert
Joined: 02 Sep 2009
Posts: 43831
Re: A group of 5 students bought movie tickets in one row next [#permalink]

### Show Tags

12 Aug 2013, 02:05
1
KUDOS
Expert's post
1
This post was
BOOKMARKED
Countdown wrote:
A group of 5 students bought movie tickets in one row next to each other. If Bob and Lisa are in this group, what is the probability that Bob and Lisa will each sit next to only one of the four other students from the group?

(A)5%
(B)10%
(C)15%
(D)20%
(E)25%

Can somebody plz clarify that the answer to this prob is 4!*2 which I am getting, but the answer in the book is given something else.

The question basically asks about the probability that Bob and Lisa sit at the ends.

The total # of sitting arrangements is 5!.

Desired arrangement is either BXYZL or LXYZB. Now, XYZ can be arranged in 3! ways, therefore total # of favorable arrangements is 2*3!.

P=(favorable)/(total)=(2*3!)/5!=1/10.

_________________
Director
Joined: 14 Dec 2012
Posts: 832
Location: India
Concentration: General Management, Operations
GMAT 1: 700 Q50 V34
GPA: 3.6

### Show Tags

12 Aug 2013, 02:05
Countdown wrote:
A group of 5 students bought movie tickets in one row next to each other. If Bob and Lisa are in this group,
what is the number of ways of seating if both of them will sit next to only one other student from the group?

Can somebody plz clarify that the answer to this prob is 4!*2 which I am getting, but the answer in the book is given something else.

LET SAY THAT BOB = B ..LISA = L
LET ONE OTHER GUY = X
NOW see question is saying....B AND L will sit next to this GUY only I.E X.
what you have done is you assumed that question is asking that B and L will sit together.
so according to given condition X cannot sit at the corner seat because in that case both B and L cant sit next to X.
so FOR X we can make hime arrange in 3!ways and B and L can be arranged in 2! ways.
therefore total ways = $$3!*2!$$

hope it helps.
_________________

When you want to succeed as bad as you want to breathe ...then you will be successfull....

GIVE VALUE TO OFFICIAL QUESTIONS...

learn AWA writing techniques while watching video : http://www.gmatprepnow.com/module/gmat-analytical-writing-assessment

Senior Manager
Joined: 10 Jul 2013
Posts: 324
Re: A group of 5 students bought movie tickets in one row next [#permalink]

### Show Tags

12 Aug 2013, 09:53
1
KUDOS
1
This post was
BOOKMARKED
Countdown wrote:
A group of 5 students bought movie tickets in one row next to each other. If Bob and Lisa are in this group, what is the probability that Bob and Lisa will each sit next to only one of the four other students from the group?

(A) 5%
(B) 10%
(C) 15%
(D) 20%
(E) 25%

Can somebody plz clarify that the answer to this prob is 4!*2 which I am getting, but the answer in the book is given something else.

use this diagram : it can help
Attachments

bob lisa.png [ 24.68 KiB | Viewed 2894 times ]

_________________

Asif vai.....

Non-Human User
Joined: 09 Sep 2013
Posts: 13816
Re: A group of 5 students bought movie tickets in one row next [#permalink]

### Show Tags

13 Mar 2015, 03:41
Hello from the GMAT Club BumpBot!

Thanks to another GMAT 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.
_________________
Non-Human User
Joined: 09 Sep 2013
Posts: 13816
Re: A group of 5 students bought movie tickets in one row next [#permalink]

### Show Tags

26 Mar 2017, 01:37
Hello from the GMAT Club BumpBot!

Thanks to another GMAT 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.
_________________
Re: A group of 5 students bought movie tickets in one row next   [#permalink] 26 Mar 2017, 01:37
Display posts from previous: Sort by