Last visit was: 13 Dec 2024, 14:07 It is currently 13 Dec 2024, 14:07
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
User avatar
Konstantin Lynov
Joined: 24 Jun 2003
Last visit: 19 Sep 2004
Posts: 71
Own Kudos:
Location: Moscow
Posts: 71
Kudos: 13
Kudos
Add Kudos
Bookmarks
Bookmark this Post
User avatar
mciatto
Joined: 10 Jun 2003
Last visit: 13 Jun 2005
Posts: 132
Own Kudos:
Location: Maryland
Posts: 132
Kudos: 38
Kudos
Add Kudos
Bookmarks
Bookmark this Post
avatar
stolyar
Joined: 03 Feb 2003
Last visit: 06 May 2014
Posts: 1,012
Own Kudos:
Posts: 1,012
Kudos: 1,752
Kudos
Add Kudos
Bookmarks
Bookmark this Post
User avatar
mciatto
Joined: 10 Jun 2003
Last visit: 13 Jun 2005
Posts: 132
Own Kudos:
Location: Maryland
Posts: 132
Kudos: 38
Kudos
Add Kudos
Bookmarks
Bookmark this Post
stolyar
take places? how many places are there? three as usual?

There are total 25 people. I assume that all the chances should be considered equal and that there are three prize places.
Thus, each out of 25 people can take 3 places = 3^25

Counting only members of the team 3^5 :roll:


I read the question to mean "In how many ways can the people on the five-person team place in the top five"

This could mean that person 1 places third and his four teammates dont even place.

You are counting every single combination of the placements of all 25 individuals.

What do you think?
User avatar
mciatto
Joined: 10 Jun 2003
Last visit: 13 Jun 2005
Posts: 132
Own Kudos:
Location: Maryland
Posts: 132
Kudos: 38
Kudos
Add Kudos
Bookmarks
Bookmark this Post
stolyar
take places? how many places are there? three as usual? or 25?

There are total 25 people. I assume that all the chances should be considered equal.

25!/5!*20!

Am I right? Am I wrong? Or am I just dreaming?


Ignore my comments...your post changed!
User avatar
mciatto
Joined: 10 Jun 2003
Last visit: 13 Jun 2005
Posts: 132
Own Kudos:
Location: Maryland
Posts: 132
Kudos: 38
Kudos
Add Kudos
Bookmarks
Bookmark this Post
stolyar
take places? how many places are there? three as usual? or 25?

There are total 25 people. I assume that all the chances should be considered equal.

25!/5!*20!

Am I right? Am I wrong? Or am I just dreaming?


Your answer equals about 53000....does that even make sense for arranging five people? I took this to mean that if _ _ _ _ _ are the five places, the combinations could be:

1 _ _ _ _ or
_ 5 _ _ _ or

_ 3_ 4 1

Where the blanks represent places taken by people NOT on the five person team, but of some of the other 20.

SO...

If only one member places, it could be:

1 _ _ _ _ or
_ 1 _ _ _ or
_ _ 1 _ _ or
_ _ _ 1 _ or
_ _ _ _ 1

Now multiply this by 5 to get all 5 members = 25 combs.

OK, so if two members place, we have more...

1 2 _ _ _
1 _ 2 _ _
1 _ _ 2 _
1 _ _ _ 2
_ 1 2 _ _
_ 1 _ 2 _
_ 1 _ _ 2
_ _ 1 2 _
_ _ 1 _ 2
_ _ _ 1 2

So there are ten here, but we have to multiply this by 5 * 4 to cover all members. So that equals 200.

Now for three we alse have 10 combs (5C3) but we multiply this by 5 * 4 * 3 to get 10 * 60 = 600

For four we get 5C4 = 5 * 5*4*3*2 = 600

for five we get 5! = 120

So lets add these up (my answer has obviously changed)

25 + 200 + 600 + 600 + 120 = 1545

Comments?
User avatar
mciatto
Joined: 10 Jun 2003
Last visit: 13 Jun 2005
Posts: 132
Own Kudos:
Location: Maryland
Posts: 132
Kudos: 38
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Konstantin Lynov
A five sportsmen team takes part in swimming competition with other 20 sportsmen. In how many ways could the members of a team take places in that competition?


In case "take places" means the first three places, then the answer becomes...

3C1 * 5 = 15 PLUS
3C2 * 5 * 4 = 60 PLUS
3C3 * 5 * 4 * 3 = 60

Answer = 135

See above for a more "complicated" explanation..now I will take a nap...
User avatar
Konstantin Lynov
Joined: 24 Jun 2003
Last visit: 19 Sep 2004
Posts: 71
Own Kudos:
Location: Moscow
Posts: 71
Kudos: 13
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Since places are all unique, it is a promultation problem. The answer is 25A5.
User avatar
AkamaiBrah
User avatar
GMAT Instructor
Joined: 07 Jul 2003
Last visit: 24 Jun 2009
Posts: 392
Own Kudos:
Location: New York NY 10024
Concentration: Finance
Schools:Haas, MFE; Anderson, MBA; USC, MSEE
Posts: 392
Kudos: 496
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Konstantin Lynov
Since places are all unique, it is a promultation problem. The answer is 25A5.


Another simple way to think of this:

Person1 has 25 possible places
Person2 has 24, etc.

hence, 25x24x23x22x21 or 25P5.
User avatar
mciatto
Joined: 10 Jun 2003
Last visit: 13 Jun 2005
Posts: 132
Own Kudos:
Location: Maryland
Posts: 132
Kudos: 38
Kudos
Add Kudos
Bookmarks
Bookmark this Post
AkamaiBrah
Konstantin Lynov
Since places are all unique, it is a promultation problem. The answer is 25A5.

Another simple way to think of this:

Person1 has 25 possible places
Person2 has 24, etc.

hence, 25x24x23x22x21 or 25P5.


Akamai,
Great point. Since "to place" in a competition, generally means to come in the top three (gold, silver, bronze) or sometimes five, thats where I was coming from. Your answer is no doubt the best.
User avatar
AkamaiBrah
User avatar
GMAT Instructor
Joined: 07 Jul 2003
Last visit: 24 Jun 2009
Posts: 392
Own Kudos:
Location: New York NY 10024
Concentration: Finance
Schools:Haas, MFE; Anderson, MBA; USC, MSEE
Posts: 392
Kudos: 496
Kudos
Add Kudos
Bookmarks
Bookmark this Post
mciatto
AkamaiBrah
Konstantin Lynov
Since places are all unique, it is a promultation problem. The answer is 25A5.

Another simple way to think of this:

Person1 has 25 possible places
Person2 has 24, etc.

hence, 25x24x23x22x21 or 25P5.

Akamai,
Great point. Since "to place" in a competition, generally means to come in the top three (gold, silver, bronze) or sometimes five, thats where I was coming from. Your answer is no doubt the best.


When making up "GMAT"-type questions, one must be careful not to assume knowledge not generally known by all countries, people, etc. While I will assume everyone knows what dice are, I will always explain a card game, or how chess piece work, or define words (such as "place") that can be ambiguous especially to non-American readers. I try to be very careful as to not make any unwarranted assumptions.

All poster should take note of this and try to edit your problems to be as unambiguous as possible.



Archived Topic
Hi there,
This topic has been closed and archived due to inactivity or violation of community quality standards. No more replies are possible here.
Where to now? Join ongoing discussions on thousands of quality questions in our Data Sufficiency (DS) Forum
Still interested in this question? Check out the "Best Topics" block above for a better discussion on this exact question, as well as several more related questions.
Thank you for understanding, and happy exploring!
Moderators:
Math Expert
97873 posts
Senior Moderator - Masters Forum
3116 posts
GMAT Tutor
1930 posts