Find all School-related info fast with the new School-Specific MBA Forum

It is currently 21 Sep 2014, 20:33

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.

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

500 - 600 level question

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
Intern
Intern
avatar
Joined: 27 Sep 2009
Posts: 41
Followers: 0

Kudos [?]: 11 [0], given: 4

500 - 600 level question [#permalink] New post 12 Jun 2010, 04:40
00:00
A
B
C
D
E

Difficulty:

(N/A)

Question Stats:

85% (01:00) correct 15% (01:40) wrong based on 19 sessions
There are a total of 19 students in Mr. Schmidt's gym class. Over the course of a badminton unit, each of the 19 students will compete exactly once against every other student in the class. How many total games of badminton will be played?

171

220

222

340

222
Intern
Intern
avatar
Joined: 09 Jun 2010
Posts: 22
Followers: 0

Kudos [?]: 0 [0], given: 2

GMAT ToolKit User
Re: 500 - 600 level question [#permalink] New post 12 Jun 2010, 10:20
From my understanding, each player hast to play vs every other player in the class except himself:
19*18 = 342

This needs to be divided by 2, because otherwise we would count "play & re-play" (A vs B and B vs A - but we don't need the second game).

We end up with:

342/2 = 171


Hope I didn't mix up anything...

ADD:

I guess, official/easiest way would be \frac{n!}{k!(n-k)!}

n! = 19 students in class
k! = we take 2 students (for the game) as our "event"

again - 171 games in total
Manager
Manager
avatar
Joined: 07 Jun 2010
Posts: 50
Location: United States
Followers: 1

Kudos [?]: 8 [0], given: 7

Re: 500 - 600 level question [#permalink] New post 12 Jun 2010, 21:41
Total students = 19
so 1st student will play against 18 , 2nd play against 17 (since 1st already played with him) and so on

so 18+17+16+......+1 = 19*9 = 171
Manager
Manager
avatar
Joined: 05 Mar 2010
Posts: 220
Followers: 1

Kudos [?]: 23 [0], given: 8

Re: 500 - 600 level question [#permalink] New post 12 Jun 2010, 23:29
Easy and shortest way

its like selecting 2 students out 19 = 19C2 = 171
_________________

Success is my Destiny

Re: 500 - 600 level question   [#permalink] 12 Jun 2010, 23:29
    Similar topics Author Replies Last post
Similar
Topics:
Manhattan GMAT 500-600 Level questions. selfishmofo 0 10 Nov 2013, 19:15
3 500-600 level question to 600-700 level questions Aristocrat 5 28 Dec 2012, 00:29
Experts publish their posts in the topic Need quant 500 and 600 level difficulty questions. I prab2012 4 03 Oct 2012, 19:49
1 600 level question shekar123 10 08 Jun 2010, 20:09
600 level questions jadomakoh 1 04 Dec 2007, 11:18
Display posts from previous: Sort by

500 - 600 level question

  Question banks Downloads My Bookmarks Reviews Important topics  


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

Powered by phpBB © phpBB Group and phpBB SEO

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®.