It is currently 13 Dec 2017, 05:18

Decision(s) Day!:

CHAT Rooms | Ross R1 | Kellogg R1 | Darden R1 | Tepper R1


Close

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
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.

Close

Request Expert Reply

Confirm Cancel

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

The 8 leaders of the G8 nations convene in Rome and stand in a row as

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

3 KUDOS received
Retired Moderator
avatar
Joined: 29 Apr 2015
Posts: 889

Kudos [?]: 1916 [3], given: 302

Location: Switzerland
Concentration: Economics, Finance
Schools: LBS MIF '19
WE: Asset Management (Investment Banking)
GMAT ToolKit User Premium Member
The 8 leaders of the G8 nations convene in Rome and stand in a row as [#permalink]

Show Tags

New post 18 Aug 2015, 11:02
3
This post received
KUDOS
7
This post was
BOOKMARKED
00:00
A
B
C
D
E

Difficulty:

  75% (hard)

Question Stats:

61% (01:13) correct 39% (01:26) wrong based on 140 sessions

HideShow timer Statistics

The 8 leaders of the G8 nations convene in Rome and stand in a row as they get ready to have some pictures of them taken by the press. What is the probability that the picture that the New York Times' editors will randomly select for publishing the next day is one in which Berlusconi is not standing next to Obama? (assuming that there are pictures of all possible standing arrangements).

A. 1/8
B. 1/4
C. 1/2
D. 3/4
E. 7/8
[Reveal] Spoiler: OA

_________________

Saving was yesterday, heat up the gmatclub.forum's sentiment by spending KUDOS!

PS Please send me PM if I do not respond to your question within 24 hours.

Kudos [?]: 1916 [3], given: 302

Expert Post
3 KUDOS received
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 42578

Kudos [?]: 135467 [3], given: 12695

The 8 leaders of the G8 nations convene in Rome and stand in a row as [#permalink]

Show Tags

New post 18 Aug 2015, 12:33
3
This post received
KUDOS
Expert's post
3
This post was
BOOKMARKED
reto wrote:
The 8 leaders of the G8 nations convene in Rome and stand in a row as they get ready to have some pictures of them taken by the press. What is the probability that the picture that the New York Times' editors will randomly select for publishing the next day is one in which Berlusconi is not standing next to Obama? (assuming that there are pictures of all possible standing arrangements).

A. 1/8
B. 1/4
C. 1/2
D. 3/4
E. 7/8


Glue those two together. We'd have 7 units: 1, 2, 3, 4, 5, 6, and {Berlusconi, Obama}. These 7 units can be arranged in 7! ways. Berlusconi and Obama within their unit can be arranged in 2! ways. Thus the total number of ways to arrange 8 leaders so that Berlusconi and Obama to stand together is 7!*2!.

8 people without any restriction can be arranged in 8! ways, thus in 8! - 7!*2! arrangements Berlusconi and Obama will not not be standing together.

\(P = \frac{8! - 7!*2!}{8!}=1 - \frac{7!*2!}{8!} = 1 - \frac{1}{4} = \frac{3}{4}\).

Answer: D.
_________________

New to the Math Forum?
Please read this: Ultimate GMAT Quantitative Megathread | All You Need for Quant | PLEASE READ AND FOLLOW: 12 Rules for Posting!!!

Resources:
GMAT Math Book | Triangles | Polygons | Coordinate Geometry | Factorials | Circles | Number Theory | Remainders; 8. Overlapping Sets | PDF of Math Book; 10. Remainders | GMAT Prep Software Analysis | SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) | Tricky questions from previous years.

Collection of Questions:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
Extra-hard Quant Tests with Brilliant Analytics

Kudos [?]: 135467 [3], given: 12695

1 KUDOS received
Manager
Manager
User avatar
Joined: 14 Mar 2014
Posts: 148

Kudos [?]: 176 [1], given: 124

GMAT 1: 710 Q50 V34
Re: The 8 leaders of the G8 nations convene in Rome and stand in a row as [#permalink]

Show Tags

New post 18 Aug 2015, 19:13
1
This post received
KUDOS
reto wrote:
The 8 leaders of the G8 nations convene in Rome and stand in a row as they get ready to have some pictures of them taken by the press. What is the probability that the picture that the New York Times' editors will randomly select for publishing the next day is one in which Berlusconi is not standing next to Obama? (assuming that there are pictures of all possible standing arrangements).

A. 1/8
B. 1/4
C. 1/2
D. 3/4
E. 7/8


Probability = \(\frac{Favorable cases}{Total no. of cases possible}\)

Total no. of cases = 8!

Let us consider the cases in which Obama and Berlusconi Stand next to each other :-

Consider Obama and Berlusconi as one single unit.
Thus in total there will be 7 members who are supposed to be arranged in 7 places = 7!
Obama and Berlusconi can interchange their places( i.e. OB or BO ) = 2 ways
Thus total no. of ways = 7! * 2

No. of cases in which O and B don't stand next to each other = Total no. of cases - No. of cases in which O and B stand next to each other
= 8! - (7! *2 )

Probability = \(\frac{8! - (7!*2)}{8!}\)
= 3/4
_________________

I'm happy, if I make math for you slightly clearer
And yes, I like kudos
¯\_(ツ)_/¯ :-)

Kudos [?]: 176 [1], given: 124

Intern
Intern
avatar
Joined: 24 Mar 2015
Posts: 9

Kudos [?]: 1 [0], given: 10

Schools: ISB '16
Re: The 8 leaders of the G8 nations convene in Rome and stand in a row as [#permalink]

Show Tags

New post 02 Dec 2015, 12:07
total ways=8!

Consider 2 people standing together as 1 entity...so 7 people in 7! ways....n b/w these 2 people 2 ways..so 7!*2!
Thus
1−7!∗2!/8!=1−1/4=3/4

Kudos [?]: 1 [0], given: 10

Board of Directors
User avatar
P
Joined: 17 Jul 2014
Posts: 2697

Kudos [?]: 447 [0], given: 207

Location: United States (IL)
Concentration: Finance, Economics
GMAT 1: 650 Q49 V30
GPA: 3.92
WE: General Management (Transportation)
GMAT ToolKit User Premium Member Reviews Badge
Re: The 8 leaders of the G8 nations convene in Rome and stand in a row as [#permalink]

Show Tags

New post 22 Feb 2016, 19:28
oh man..tried to get it as fast as possible..and did not subtract from 1..picked 1/4...:(
although I did the right thing...
stick the two guys together -> arrange in 7!. these 2 can be arranged in 2!.
now this, divide by 8! of ways.
from total number of ways -> subtract the number of ways in which the guys sit together.
probability that they will sit together - 1/4
that they will not
1- 1/4 = 3/4

Kudos [?]: 447 [0], given: 207

Non-Human User
User avatar
Joined: 09 Sep 2013
Posts: 14878

Kudos [?]: 287 [0], given: 0

Premium Member
Re: The 8 leaders of the G8 nations convene in Rome and stand in a row as [#permalink]

Show Tags

New post 28 Sep 2017, 08:29
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.
_________________

GMAT Books | GMAT Club Tests | Best Prices on GMAT Courses | GMAT Mobile App | Math Resources | Verbal Resources

Kudos [?]: 287 [0], given: 0

Re: The 8 leaders of the G8 nations convene in Rome and stand in a row as   [#permalink] 28 Sep 2017, 08:29
Display posts from previous: Sort by

The 8 leaders of the G8 nations convene in Rome and stand in a row as

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  


GMAT Club MBA Forum Home| About| Terms and Conditions| GMAT Club Rules| Contact| Sitemap

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

Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.