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

It is currently 21 Nov 2018, 10:43

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 in November
PrevNext
SuMoTuWeThFrSa
28293031123
45678910
11121314151617
18192021222324
2526272829301
Open Detailed Calendar
  • All GMAT Club Tests are Free and open on November 22nd in celebration of Thanksgiving Day!

     November 22, 2018

     November 22, 2018

     10:00 PM PST

     11:00 PM PST

    Mark your calendars - All GMAT Club Tests are free and open November 22nd to celebrate Thanksgiving Day! Access will be available from 0:01 AM to 11:59 PM, Pacific Time (USA)
  • Key Strategies to Master GMAT SC

     November 24, 2018

     November 24, 2018

     07:00 AM PST

     09:00 AM PST

    Attend this webinar to learn how to leverage Meaning and Logic to solve the most challenging Sentence Correction Questions.

There are 8 teams in a certain league and each team plays

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

Hide Tags

Intern
Intern
avatar
B
Joined: 09 Apr 2017
Posts: 24
Premium Member CAT Tests
Re: There are 8 teams in a certain league and each team plays  [#permalink]

Show Tags

New post 25 Aug 2017, 23:46
Try this watch this, similar examples-

Try pick up from Khan academy to built the foundation for permutations and combinations.

The questions are very interesting too.


Similar questions found in:
https://www.khanacademy.org/math/precal ... mbinations

Posted from my mobile device
Intern
Intern
avatar
B
Joined: 13 Oct 2017
Posts: 3
GMAT 1: 530 Q43 V20
GPA: 3.99
Reviews Badge
Re: There are 8 teams in a certain league and each team plays  [#permalink]

Show Tags

New post 13 Oct 2017, 23:06
Let me sort this in a non conventional way. Since there are 8 teams let us consider them as A,B,C,D,E,F,G,H

Now A can play with B,C,D,E,F,G,H so total 7 matches
Now B can play with all others other than itself and A since it already played with A in previous step
So total 6 matches- C,D,E,F,G,H total 6 matches
Now C can play with D,E,F,G,H. Total 5 matches
Now D can play with E,F,G,H total 4 matches
Now E can play with F,G,H total 3 matches
Now F can play with G,H total 2 matches
Now G can play with H total 1 match
So now if we add all of these
7+6+5+4+3+2+1 = 28 is our answer.

Hope this helps





Sent from my iPhone using GMAT Club Forum mobile app
Director
Director
User avatar
S
Joined: 17 Dec 2012
Posts: 629
Location: India
There are 8 teams in a certain league and each team plays  [#permalink]

Show Tags

New post 14 Oct 2017, 01:54
sarb wrote:
There are 8 teams in a certain league and each team plays each of the other teams exactly once. If each game is played by 2 teams, what is the total number of games played?

A. 15
B. 16
C. 28
D. 56
E. 64

One needs to always find n and r in permutation and combination problems. n is the total number from which you choose and r is how many you choose at a time which makes it one possibility. If the order of the entities chosen at a time, does not matter as in this case, it is nCr , otherwise it is nPr.

n and r in this problem are 8 and 2 respectively and the total number of games played is 8C2=28. Hence C.
_________________

Srinivasan Vaidyaraman
Sravna Holistic Solutions
http://www.sravnatestprep.com

Holistic and Systematic Approach

VP
VP
User avatar
P
Joined: 09 Mar 2016
Posts: 1115
Re: There are 8 teams in a certain league and each team plays  [#permalink]

Show Tags

New post 25 Dec 2017, 13:22
Bunuel wrote:
sarb wrote:
There are 8 teams in a certain league and each team plays each of the other teams exactly once. If each game is played by 2 teams, what is the total number of games played?

A. 15
B. 16
C. 28
D. 56
E. 64


The total # of games played would be equal to the # of different pairs possible from 8 teams, which is \(C^2_{8}=28\).

Answer: C.

P.S. Please read and follow: http://gmatclub.com/forum/rules-for-pos ... 33935.html Pay attention ot the points #3 and #8.


Bunuel lets say teams are as follows: A, B, C, D, E, F, G, H. So by using the simple combinatorics formula how do we exclude repeated teams ? I mean if A played with B - this is one game, and it could be also B WITH A ? yeah sounds a bit silly :) but how do we exclude such repetition :? thanks! :)
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 50730
Re: There are 8 teams in a certain league and each team plays  [#permalink]

Show Tags

New post 25 Dec 2017, 20:07
dave13 wrote:
Bunuel wrote:
sarb wrote:
There are 8 teams in a certain league and each team plays each of the other teams exactly once. If each game is played by 2 teams, what is the total number of games played?

A. 15
B. 16
C. 28
D. 56
E. 64


The total # of games played would be equal to the # of different pairs possible from 8 teams, which is \(C^2_{8}=28\).

Answer: C.

P.S. Please read and follow: http://gmatclub.com/forum/rules-for-pos ... 33935.html Pay attention ot the points #3 and #8.


Bunuel lets say teams are as follows: A, B, C, D, E, F, G, H. So by using the simple combinatorics formula how do we exclude repeated teams ? I mean if A played with B - this is one game, and it could be also B WITH A ? yeah sounds a bit silly :) but how do we exclude such repetition :? thanks! :)


8C2 gives the number of different unordered pairs possible from 8:
(A, B)
(A, C)
...
(B, H)
...
(G, H)

So, (A, B) is there only once (there is no (B, A) there)

Similar questions to practice:
http://gmatclub.com/forum/how-many-diag ... 01540.html
http://gmatclub.com/forum/if-10-persons ... 10622.html
http://gmatclub.com/forum/10-business-e ... 26163.html
http://gmatclub.com/forum/how-many-diff ... 29992.html
http://gmatclub.com/forum/15-chess-play ... 55939.html
http://gmatclub.com/forum/there-are-5-c ... 27235.html
http://gmatclub.com/forum/if-each-parti ... 42222.html
http://gmatclub.com/forum/there-are-8-t ... 34582.html
http://gmatclub.com/forum/there-are-8-t ... 32366.html
http://gmatclub.com/forum/in-a-kickball ... 61846.html
http://gmatclub.com/forum/there-are-8-t ... 34582.html
_________________

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

VP
VP
User avatar
P
Joined: 09 Mar 2016
Posts: 1115
There are 8 teams in a certain league and each team plays  [#permalink]

Show Tags

New post 18 Mar 2018, 07:12
Bunuel wrote:
sarb wrote:
There are 8 teams in a certain league and each team plays each of the other teams exactly once. If each game is played by 2 teams, what is the total number of games played?

A. 15
B. 16
C. 28
D. 56
E. 64


The total # of games played would be equal to the # of different pairs possible from 8 teams, which is \(C^2_{8}=28\).

Answer: C.

P.S. Please read and follow: http://gmatclub.com/forum/rules-for-pos ... 33935.html Pay attention ot the points #3 and #8.



Bunuel you know I got confused by your shortcut solution :) until figured out all possible combinations in details . you know what surprises how this expression \(C^2_{8}=28\)
excludes the possibility of playing more than one game by two distinct teams, also it exludes repeated games like AB and BA....

let 8 teams be A, B, C, D, E, F, G, H

NUMBER OF GAMES PLAYES BY TWO TEAMS AS FOLLOWS:

AB BC CD DE EF
AC BD CE DF EG
AD BE CF DG EH
AE BF CG DH
AF BG CH
AG BH
AH

niks18 your comments are always appreciated :) have a great day :)
PS Forum Moderator
avatar
D
Joined: 25 Feb 2013
Posts: 1217
Location: India
GPA: 3.82
GMAT ToolKit User Premium Member Reviews Badge
Re: There are 8 teams in a certain league and each team plays  [#permalink]

Show Tags

New post 19 Mar 2018, 10:00
1
dave13 wrote:
Bunuel wrote:
sarb wrote:
There are 8 teams in a certain league and each team plays each of the other teams exactly once. If each game is played by 2 teams, what is the total number of games played?

A. 15
B. 16
C. 28
D. 56
E. 64


The total # of games played would be equal to the # of different pairs possible from 8 teams, which is \(C^2_{8}=28\).

Answer: C.

P.S. Please read and follow: http://gmatclub.com/forum/rules-for-pos ... 33935.html Pay attention ot the points #3 and #8.



Bunuel you know I got confused by your shortcut solution :) until figured out all possible combinations in details . you know what surprises how this expression \(C^2_{8}=28\)
excludes the possibility of playing more than one game by two distinct teams, also it exludes repeated games like AB and BA....

let 8 teams be A, B, C, D, E, F, G, H

NUMBER OF GAMES PLAYES BY TWO TEAMS AS FOLLOWS:

AB BC CD DE EF
AC BD CE DF EG
AD BE CF DG EH
AE BF CG DH
AF BG CH
AG BH
AH

niks18 your comments are always appreciated :) have a great day :)


Hi dave13

it is clearly mentioned in the question that each team plays against other team only Once. Hence you can safely use the formula provided by Bunuel. and if we say A plays against B then its same as saying B plays against A so order does not matter here. Hence there will be only one combination with A & B taken together and not two different combinations as stated by you AB & BA.
Manager
Manager
User avatar
B
Joined: 26 Feb 2018
Posts: 59
WE: Sales (Internet and New Media)
Re: There are 8 teams in a certain league and each team plays  [#permalink]

Show Tags

New post 24 May 2018, 23:22
sarb wrote:
There are 8 teams in a certain league and each team plays each of the other teams exactly once. If each game is played by 2 teams, what is the total number of games played?

A. 15
B. 16
C. 28
D. 56
E. 64


8C2 ways , 28 Ans
_________________

" Can't stop learning and failing"

GMAT Club Bot
Re: There are 8 teams in a certain league and each team plays &nbs [#permalink] 24 May 2018, 23:22

Go to page   Previous    1   2   [ 28 posts ] 

Display posts from previous: Sort by

There are 8 teams in a certain league and each team plays

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


Copyright

GMAT Club MBA Forum Home| About| Terms and Conditions and Privacy Policy| 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®.