NEW HERE? LEARN MORE
closeclose
Last visit was: 23 Apr 2024, 19:01 It is currently 23 Apr 2024, 19:01
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

In a group of 8 semifinalists, all but 2 will advance to the final rou

SORT BY:
Date
Kudos
Tags:
Find Similar Topics 
Show Tags
Hide Tags
User avatar
L
Bunuel
Math Expert
Joined: 02 Sep 2009
Posts: 92883
Own Kudos [?]: 618603 [22]
Given Kudos: 81563
Send PM
CAT Tests Forum Quiz Mode
In a group of 8 semifinalists, all but 2 will advance to the final rou [#permalink] New post   22 May 2016, 14:46
1
Kudos
21
Bookmarks
Expert Reply
00:00
A
B
C
D
E

Difficulty:

85% (hard)

Question Stats:

35% (01:29) correct 65% (01:44) wrong based on 214 sessions
Hide Show timer Statistics
In a group of 8 semifinalists, all but 2 will advance to the final round. If in the final round only the top 3 will be awarded medals, then how many groups of medal winners are possible?

(A) 20
(B) 56
(C) 120
(D) 560
(E) 720
ShowHide Answer
Official Answer
B
Most Helpful Reply
User avatar
L
chetan2u
RC & DI Moderator
Joined: 02 Aug 2009
Status:Math and DI Expert
Posts: 11161
Own Kudos [?]: 31870 [6]
Given Kudos: 290
Send PM
Reviews Badge
Re: In a group of 8 semifinalists, all but 2 will advance to the final rou [#permalink] New post   22 May 2016, 20:26
3
Kudos
3
Bookmarks
Expert Reply
Bunuel wrote:
In a group of 8 semifinalists, all but 2 will advance to the final round. If in the final round only the top 3 will be awarded medals, then how many groups of medal winners are possible?

(A) 20
(B) 56
(C) 120
(D) 560
(E) 720


Hi,

there are two points to remember-


1) Is it important here that how many go into finals... NO....
what is important is HOW many get medals..3
finally these 3 can be any of the 8 - \(8C3 = \frac{8!}{5!3!} = \frac{8*7*6}{3*2}=56\)

2) Is order important...NO
we are looking for groups only..

ans 56
B
General Discussion
avatar
B
dabhishek87
Manager
Manager
Joined: 19 Aug 2015
Posts: 64
Own Kudos [?]: 13 [0]
Given Kudos: 24
Location: India
GMAT 1: 650 Q49 V30
Send PM
Re: In a group of 8 semifinalists, all but 2 will advance to the final rou [#permalink] New post   09 Jun 2017, 10:11
For this problem we have to select 3 semifinalists out of 8 so
\(8_C_3\)
Answer B
avatar
B
Palaksehgal3
Intern
Intern
Joined: 30 Mar 2017
Posts: 8
Own Kudos [?]: 0 [0]
Given Kudos: 74
Send PM
Re: In a group of 8 semifinalists, all but 2 will advance to the final rou [#permalink] New post   03 Jul 2017, 02:15
As per the question, only 6 semifinalists made it to the 3rd round.
So why is the answer not 6c3?
User avatar
L
Bunuel
Math Expert
Joined: 02 Sep 2009
Posts: 92883
Own Kudos [?]: 618603 [3]
Given Kudos: 81563
Send PM
CAT Tests Forum Quiz Mode
Re: In a group of 8 semifinalists, all but 2 will advance to the final rou [#permalink] New post   03 Jul 2017, 02:30
3
Kudos
Expert Reply
Palaksehgal3 wrote:
As per the question, only 6 semifinalists made it to the 3rd round.
So why is the answer not 6c3?


Yes, but initial number is still 8. Do we know which 2 won't advance to the final? No. So, the size of the group we are selecting from is still 8.

In a group of 8 semifinalists, all but 2 will advance to the final round. If in the final round only the top 3 will be awarded medals, then how many groups of medal winners are possible?

(A) 20
(B) 56
(C) 120
(D) 560
(E) 720

Intermediary step about "all but 2 will advance to the final round" is just to confuse us: any group of 3 is equally likely to win, so we can skip this part and directly calculate ways to choose 3 contestants out of 8: \(C3_8=56\).

Answer: B.
avatar
B
Palaksehgal3
Intern
Intern
Joined: 30 Mar 2017
Posts: 8
Own Kudos [?]: 0 [0]
Given Kudos: 74
Send PM
Re: In a group of 8 semifinalists, all but 2 will advance to the final rou [#permalink] New post   03 Jul 2017, 02:42
Bunuel wrote:
Palaksehgal3 wrote:
As per the question, only 6 semifinalists made it to the 3rd round.
So why is the answer not 6c3?


Yes, but initial number is still 8. Do we know which 2 won't advance to the final? No. So, the size of the group we are selecting from is still 8.

In a group of 8 semifinalists, all but 2 will advance to the final round. If in the final round only the top 3 will be awarded medals, then how many groups of medal winners are possible?

(A) 20
(B) 56
(C) 120
(D) 560
(E) 720

Intermediary step about "all but 2 will advance to the final round" is just to confuse us: any group of 3 is equally likely to win, so we can skip this part and directly calculate ways to choose 3 contestants out of 8: \(C3_8=56\).

Answer: B.


Makes sense. Thanks Bunuel :)
I am having a hard time with probability and permutations. Could you please advise how to go about improving at it?
User avatar
L
Bunuel
Math Expert
Joined: 02 Sep 2009
Posts: 92883
Own Kudos [?]: 618603 [4]
Given Kudos: 81563
Send PM
CAT Tests Forum Quiz Mode
Re: In a group of 8 semifinalists, all but 2 will advance to the final rou [#permalink] New post   03 Jul 2017, 02:44
2
Kudos
2
Bookmarks
Expert Reply
Palaksehgal3 wrote:
Bunuel wrote:
Palaksehgal3 wrote:
As per the question, only 6 semifinalists made it to the 3rd round.
So why is the answer not 6c3?


Yes, but initial number is still 8. Do we know which 2 won't advance to the final? No. So, the size of the group we are selecting from is still 8.

In a group of 8 semifinalists, all but 2 will advance to the final round. If in the final round only the top 3 will be awarded medals, then how many groups of medal winners are possible?

(A) 20
(B) 56
(C) 120
(D) 560
(E) 720

Intermediary step about "all but 2 will advance to the final round" is just to confuse us: any group of 3 is equally likely to win, so we can skip this part and directly calculate ways to choose 3 contestants out of 8: \(C3_8=56\).

Answer: B.


Makes sense. Thanks Bunuel :)
I am having a hard time with probability and permutations. Could you please advise how to go about improving at it?


Check the links below:
Combinatorics Made Easy!

Theory on Combinations

DS questions on Combinations
PS questions on Combinations

Tough and tricky questions on Combinations

Probability Made Easy!

Theory on probability problems

Data Sufficiency Questions on Probability
Problem Solving Questions on Probability

Tough Probability Questions

Hope it helps.
User avatar
bumpbot
Non-Human User
Joined: 09 Sep 2013
Posts: 32630
Own Kudos [?]: 821 [0]
Given Kudos: 0
Send PM
Re: In a group of 8 semifinalists, all but 2 will advance to the final rou [#permalink] New post   02 Apr 2024, 14:47
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
gmatclubot
Re: In a group of 8 semifinalists, all but 2 will advance to the final rou [#permalink]
02 Apr 2024, 14:47
Moderators:
Bunuel
Math Expert
92883 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