NEW HERE? LEARN MORE
closeclose
Last visit was: 26 Apr 2024, 11:21 It is currently 26 Apr 2024, 11:21
Decision Tracker
My Rewards
New posts
New comers' posts

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.
Go to My Error Log Learn more
Close
Request Expert Reply
Confirm Cancel

At a wedding reception, twelve guests sat together at a round table. A

SORT BY:
Date
Kudos
Tags:
Find Similar Topics 
Show Tags
Hide Tags
User avatar
L
Bunuel
Math Expert
Joined: 02 Sep 2009
Posts: 92948
Own Kudos [?]: 619217 [2]
Given Kudos: 81609
Send PM
CAT Tests Forum Quiz Mode
At a wedding reception, twelve guests sat together at a round table. A [#permalink] New post   07 Jul 2020, 03:04
2
Bookmarks
Expert Reply
00:00
A
B
C
D
E

Difficulty:

25% (medium)

Question Stats:

73% (01:09) correct 27% (01:45) wrong based on 62 sessions
Hide Show timer Statistics
At a wedding reception, twelve guests sat together at a round table. At the end of the meal, before they left, each guest at the table kissed all of the other guests goodbye. What was the total number of kisses?

A. 24
B. 55
C. 66
D. 78
E. 132
ShowHide Answer
Official Answer
C
User avatar
L
yashikaaggarwal
Senior Moderator - Masters Forum
Joined: 19 Jan 2020
Posts: 3137
Own Kudos [?]: 2769 [1]
Given Kudos: 1510
Location: India
Schools: Cranfield (A) Warwick MiM "23 (M)
GPA: 4
WE:Analyst (Internet and New Media)
Send PM
At a wedding reception, twelve guests sat together at a round table. A [#permalink] New post   07 Jul 2020, 04:37
1
Kudos
Total no. Of kisses = Sum of N-1 number of guests = sum of 11 positive number of guests
Sum = 11(11+1)/2
Sum = 11*12/2
Sum = 11*6
Sum = 66

Therefore total 66 kisses were been done at the table.

Alternatively,
Let the guests be 1,2,3,..........12

1 will kiss every other guest except himself.

(1,2)
(1,3),(2,3)
(1,4),(2,4),(3,4)
(1,5),(2,5),(3,5),(4,5)
(1,6),(2,6),(3,6)......,(5,6)
(1,7),(2,7),(3,7).......,(6,7)
(1,8),(2,8),(3,8).........,(7,8)
(1,9),(2,9),(3,9)..........,(8,9)
(1,10),(2,10),(3,10)........,(9,10)
(1,11),(2,11),(3,11).........,(10,11)
(1,12),(2,12),(3,12)..........,(11,12)
Total no. Of kisses = 11+10+9+8+7+6+5+4+3+2+1 = 66

Posted from my mobile device
User avatar
L
IanStewart
GMAT Tutor
Joined: 24 Jun 2008
Posts: 4128
Own Kudos [?]: 9247 [1]
Given Kudos: 91
 Q51  V47
Send PM
Re: At a wedding reception, twelve guests sat together at a round table. A [#permalink] New post   07 Jul 2020, 05:57
1
Kudos
Expert Reply
The round table is irrelevant. Every (unordered) pair of people creates one kiss, and we can pick 12C2 = (12)(11)/2! = 66 pairs of people, so that's the answer.
User avatar
L
Archit3110
GMAT Club Legend
GMAT Club Legend
Joined: 18 Aug 2017
Status:You learn more from failure than from success.
Posts: 8020
Own Kudos [?]: 4098 [0]
Given Kudos: 242
Location: India
Concentration: Sustainability, Marketing
GMAT Focus 1:
545 Q79 V79 DI73
GPA: 4
WE:Marketing (Energy and Utilities)
Send PM
GMAT ToolKit User CAT Tests
Re: At a wedding reception, twelve guests sat together at a round table. A [#permalink] New post   07 Jul 2020, 07:58
Bunuel wrote:
At a wedding reception, twelve guests sat together at a round table. At the end of the meal, before they left, each guest at the table kissed all of the other guests goodbye. What was the total number of kisses?

A. 24
B. 55
C. 66
D. 78
E. 132


this question is similar to like having handshakes amongst a set of people
total possible exchange of kisses amongst 12 people ; 12c2 ; 66
OPTION C
User avatar
D
QuantMadeEasy
Senior Manager
Senior Manager
Joined: 28 Feb 2014
Posts: 471
Own Kudos [?]: 559 [0]
Given Kudos: 74
Location: India
Concentration: General Management, International Business
GMAT 1: 570 Q49 V20
GPA: 3.97
WE:Engineering (Education)
Send PM
Re: At a wedding reception, twelve guests sat together at a round table. A [#permalink] New post   07 Jul 2020, 09:41
Step1: Understanding
Total people - 12
People required for a kiss - 2
As the order does not matter, the question is on combination

Step2: Calculation
Total number of kisses - 12C2 = 12!/10!*2! = 12*11/2 = 6*11 = 66
(D) is correct
User avatar
L
Kinshook
GMAT Club Legend
GMAT Club Legend
Joined: 03 Jun 2019
Posts: 5344
Own Kudos [?]: 3967 [0]
Given Kudos: 160
Location: India
Schools: HBS '22 CBS '22 Wharton '22
GMAT 1: 690 Q50 V34
WE:Engineering (Transportation)
Send PM
Reviews Badge
Re: At a wedding reception, twelve guests sat together at a round table. A [#permalink] New post   07 Jul 2020, 10:18
Bunuel wrote:
At a wedding reception, twelve guests sat together at a round table. At the end of the meal, before they left, each guest at the table kissed all of the other guests goodbye. What was the total number of kisses?

A. 24
B. 55
C. 66
D. 78
E. 132


Given: At a wedding reception, twelve guests sat together at a round table. At the end of the meal, before they left, each guest at the table kissed all of the other guests goodbye.
Asked: What was the total number of kisses?

Total number of kisses = 12C2 = 12*11/2 = 66

IMO C
User avatar
S
nkme2007
Manager
Manager
Joined: 11 Mar 2012
Posts: 176
Own Kudos [?]: 57 [0]
Given Kudos: 103
Location: India
Concentration: General Management, Operations
Schools: IIMB EPGP'22 (M)
GMAT 1: 670 Q50 V31
GPA: 4
WE:Project Management (Real Estate)
Send PM
Reviews Badge
Re: At a wedding reception, twelve guests sat together at a round table. A [#permalink] New post   07 Jul 2020, 21:35
Bunuel wrote:
At a wedding reception, twelve guests sat together at a round table. At the end of the meal, before they left, each guest at the table kissed all of the other guests goodbye. What was the total number of kisses?

A. 24
B. 55
C. 66
D. 78
E. 132


Total number of kisses = 12C2 = 12*11/2 = 66

OA: C
GMAT Club Bot
gmatclubot
Re: At a wedding reception, twelve guests sat together at a round table. A [#permalink]
07 Jul 2020, 21:35
Moderators:
Bunuel
Math Expert
92947 posts
yashikaaggarwal
Senior Moderator - Masters Forum
3137 posts

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne
Main navigation
GMAT Resources
Partners
MBA Resources
www.gmac.com|www.mba.com | | GMAT Club Rules | Terms and Conditions