GMAT Question of the Day - Daily to your Mailbox; hard ones only

It is currently 09 Dec 2019, 12:08

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

6 people meet for a business lunch. Each person shakes hands once with

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

Hide Tags

Find Similar Topics 
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 59623
6 people meet for a business lunch. Each person shakes hands once with  [#permalink]

Show Tags

New post 12 May 2016, 01:56
1
3
00:00
A
B
C
D
E

Difficulty:

  15% (low)

Question Stats:

74% (00:42) correct 26% (00:50) wrong based on 161 sessions

HideShow timer Statistics

Intern
Intern
avatar
Joined: 07 May 2016
Posts: 25
6 people meet for a business lunch. Each person shakes hands once with  [#permalink]

Show Tags

New post 12 May 2016, 08:07
1
Bunuel wrote:
6 people meet for a business lunch. Each person shakes hands once with each other person present. How many handshakes take place?

A. 30
B. 21
C. 18
D. 15
E. 10


Hi
the formula to count handshakes is \(\frac{n(n-1)}{2}\)
Where n is the number of people

=> 6(6-1)/2 = 6*5/2 = 30/2 = 15
=> the answer is D(15)

Here why:
if there are 2 people at the business lunch
=> the number of handshakes will be 1 (obviously)

people | handshakes
2 | 1
3 | 3
4 | 6
=> we can see

2 people = 1 handshakes
3 people = 2 + 1 handshakes
4 people = 3 + 2 +1 handshakes
5 people = 4 + 3 + 2 + 1 handshakes
6 people = 5 + 4 + 3 + 2 +1 handshakes

=> the formula will be \(\frac{n(n-1)}{2}\)
Current Student
User avatar
Joined: 18 Oct 2014
Posts: 796
Location: United States
GMAT 1: 660 Q49 V31
GPA: 3.98
GMAT ToolKit User
Re: 6 people meet for a business lunch. Each person shakes hands once with  [#permalink]

Show Tags

New post 12 May 2016, 11:10
3
Let's look at the logic.

Every person shakes hand with other '5'. So, 6 people shake hands with 6X5= 30 people

But in this 30 we have counted two times the total handshakes (A shakes hand with B and B shakes hand with A)

So just divide 30/2= 15 total handshakes
_________________
I welcome critical analysis of my post!! That will help me reach 700+
Intern
Intern
avatar
B
Joined: 12 Aug 2013
Posts: 45
Re: 6 people meet for a business lunch. Each person shakes hands once with  [#permalink]

Show Tags

New post 12 May 2016, 21:16
1
Its a combination problem :-

Out of 6 we just need 2 ..order doesn't matter

6c2 = 15

Thanks
Non-Human User
User avatar
Joined: 09 Sep 2013
Posts: 13730
Re: 6 people meet for a business lunch. Each person shakes hands once with  [#permalink]

Show Tags

New post 23 Nov 2018, 08:17
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 Club Bot
Re: 6 people meet for a business lunch. Each person shakes hands once with   [#permalink] 23 Nov 2018, 08:17
Display posts from previous: Sort by

6 people meet for a business lunch. Each person shakes hands once with

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





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