Check GMAT Club Decision Tracker for the Latest School Decision Releases https://gmatclub.com/AppTrack

It is currently 29 May 2017, 22:18

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

Events & Promotions in June
Open Detailed Calendar

A business school club, Friends of Foam, is throwing a party at a loca

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

Hide Tags

Director
Director
User avatar
Joined: 25 Aug 2007
Posts: 940
WE 1: 3.5 yrs IT
WE 2: 2.5 yrs Retail chain
Followers: 77

Kudos [?]: 1330 [0], given: 40

A business school club, Friends of Foam, is throwing a party at a loca [#permalink]

Show Tags

New post 20 Apr 2010, 08:11
00:00
A
B
C
D
E

Difficulty:

(N/A)

Question Stats:

50% (02:29) correct 50% (02:15) wrong based on 12 sessions

HideShow timer Statistics

A business school club, Friends of Foam, is throwing a party at a local bar. Of the business school students at the bar, 40% are first year students and 60% are second year students. Of the first year students, 40% are drinking beer, 40% are drinking mixed drinks, and 20% are drinking both. Of the second year students, 30% are drinking beer, 30% are drinking mixed drinks, and 20% are drinking both. A business school student is chosen at random. If the student is drinking beer, what is the probability that he or she is also drinking mixed drinks?

A. 2/5
B. 4/7
C. 10/17
D. 7/24
E. 7/10
[Reveal] Spoiler: OA

_________________

Want to improve your CR: http://gmatclub.com/forum/cr-methods-an-approach-to-find-the-best-answers-93146.html
Tricky Quant problems: http://gmatclub.com/forum/50-tricky-questions-92834.html
Important Grammer Fundamentals: http://gmatclub.com/forum/key-fundamentals-of-grammer-our-crucial-learnings-on-sc-93659.html

Expert Post
Math Expert
User avatar
P
Joined: 02 Sep 2009
Posts: 39064
Followers: 7757

Kudos [?]: 106585 [0], given: 11630

Re: A business school club, Friends of Foam, is throwing a party at a loca [#permalink]

Show Tags

New post 20 Apr 2010, 08:36
ykaiim wrote:
A business school club, Friends of Foam, is throwing a party at a local bar. Of
the business school students at the bar, 40% are first year students and 60% are
second year students. Of the first year students, 40% are drinking beer, 40% are
drinking mixed drinks, and 20% are drinking both. Of the second year students,
30% are drinking beer, 30% are drinking mixed drinks, and 20% are drinking
both. A business school student is chosen at random. If the student is drinking beer,
what is the probability that he or she is also drinking mixed drinks?
A. 2/5
B. 4/7
C. 10/17
D. 7/24
E. 7/10

I didn't understand what the question asked :wall . I tried to calculate but all mismatch. Please provide some explanations.


Let's say total students =100
First year=40
Second year=60

Out of the first year students: 16 drink beer (40% of 40), 16 drink mixed drinks (40% of 40) and out of these 32 students, 8 are drinking both (20% of 40). What are other 8 students drinking, we don't know.

Out of the second year students: 18 drink beer (30% of 60), 18 drink mixed drinks (30% of 60) and out of these 36 students, 12 are drinking both (20% of 60). What are other 24 students drinking, we don't know.

So total beer drinkers are 16+18=34. Out of these students 8+12=20 are drinking both beer and mixed drinks. So probability that student who is drinking beer also is drinking mixed drinks is 20/34=10/17.

Answer: C.
_________________

New to the Math Forum?
Please read this: 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

Director
Director
User avatar
Joined: 25 Aug 2007
Posts: 940
WE 1: 3.5 yrs IT
WE 2: 2.5 yrs Retail chain
Followers: 77

Kudos [?]: 1330 [0], given: 40

Re: A business school club, Friends of Foam, is throwing a party at a loca [#permalink]

Show Tags

New post 20 Apr 2010, 08:55
Bunuel wrote:
ykaiim wrote:
A business school club, Friends of Foam, is throwing a party at a local bar. Of
the business school students at the bar, 40% are first year students and 60% are
second year students. Of the first year students, 40% are drinking beer, 40% are
drinking mixed drinks, and 20% are drinking both. Of the second year students,
30% are drinking beer, 30% are drinking mixed drinks, and 20% are drinking
both. A business school student is chosen at random. If the student is drinking beer,
what is the probability that he or she is also drinking mixed drinks?
A. 2/5
B. 4/7
C. 10/17
D. 7/24
E. 7/10

I didn't understand what the question asked :wall . I tried to calculate but all mismatch. Please provide some explanations.


Let's say total students =100
First year=40
Second year=60

Out of the first year students: 16 drink beer (40% of 40), 16 drink mixed drinks (40% of 40) and out of these 32 students, 8 are drinking both (20% of 40). What are other 8 students drinking, we don't know.
I think you already sum up to 40. Where from this 8 more come?

Out of the second year students: 18 drink beer (30% of 60), 18 drink mixed drinks (30% of 60) and out of these 36 students, 12 are drinking both (20% of 60). What are other 24 students drinking, we don't know.
I think it should be 12.

So total beer drinkers are 16+18=34. Out of these students 8+12=20 are drinking both beer and mixed drinks. So probability that student who is drinking beer also is drinking mixed drinks is 20/34=10/17.

Answer: C.


One more thing, is this question asking for the ratio of above two calculations?
_________________

Want to improve your CR: http://gmatclub.com/forum/cr-methods-an-approach-to-find-the-best-answers-93146.html
Tricky Quant problems: http://gmatclub.com/forum/50-tricky-questions-92834.html
Important Grammer Fundamentals: http://gmatclub.com/forum/key-fundamentals-of-grammer-our-crucial-learnings-on-sc-93659.html

Expert Post
Math Expert
User avatar
P
Joined: 02 Sep 2009
Posts: 39064
Followers: 7757

Kudos [?]: 106585 [0], given: 11630

Re: A business school club, Friends of Foam, is throwing a party at a loca [#permalink]

Show Tags

New post 20 Apr 2010, 09:11
ykaiim wrote:
One more thing, is this question asking for the ratio of above two calculations?


Your calculation is not correct.

Step by step:

Out of the first year students: 16 drink beer (40% of 40), 16 drink mixed drinks (40% of 40) --> 16+16=32. And out of these 32 students, 8 are drinking both (20% of 40).

40-32=8 and we don't know what are they drinking (actually it doesn't matter).

Out of the second year students: 18 drink beer (30% of 60), 18 drink mixed drinks (30% of 60) --> 18+18=36. And out of these 36 students, 12 are drinking both (20% of 60).

60-36=24 and we don't know what are they drinking (actually it doesn't matter).

So total beer drinkers are 16+18=34. Out of these students 8+12=20 are drinking both beer and mixed drinks. So probability that student who is drinking beer (denominator) also is drinking mixed drinks (numerator) is: 20/34=10/17.
_________________

New to the Math Forum?
Please read this: 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

CEO
CEO
User avatar
Status: Nothing comes easy: neither do I want.
Joined: 12 Oct 2009
Posts: 2786
Location: Malaysia
Concentration: Technology, Entrepreneurship
Schools: ISB '15 (M)
GMAT 1: 670 Q49 V31
GMAT 2: 710 Q50 V35
Followers: 238

Kudos [?]: 1731 [0], given: 235

Reviews Badge
Re: A business school club, Friends of Foam, is throwing a party at a loca [#permalink]

Show Tags

New post 20 Apr 2010, 09:19
Probability = required outcomes/total outcomes

required outcomes = 20% of 40% of total + 20% of 60% of total

= 20% of (40% * x) + 20% of (60%*x) = 20% of x = .2x

total outcomes = total of those who drink beer

= 40% of 40% of x + 30% of 60% of x

= .16x + .18x = .34x

so probability = .2x/.34x = .1/.17 = 10/17

hence C
_________________

Fight for your dreams :For all those who fear from Verbal- lets give it a fight

Money Saved is the Money Earned :)

Jo Bole So Nihaal , Sat Shri Akaal

:thanks Support GMAT Club by putting a GMAT Club badge on your blog/Facebook :thanks

GMAT Club Premium Membership - big benefits and savings

Gmat test review :
http://gmatclub.com/forum/670-to-710-a-long-journey-without-destination-still-happy-141642.html

Intern
Intern
User avatar
Joined: 08 Apr 2010
Posts: 28
Followers: 1

Kudos [?]: 10 [0], given: 3

Re: A business school club, Friends of Foam, is throwing a party at a loca [#permalink]

Show Tags

New post 20 Apr 2010, 23:03
ykaiim wrote:
A business school club, Friends of Foam, is throwing a party at a local bar. Of
the business school students at the bar, 40% are first year students and 60% are
second year students. Of the first year students, 40% are drinking beer, 40% are
drinking mixed drinks, and 20% are drinking both. Of the second year students,
30% are drinking beer, 30% are drinking mixed drinks, and 20% are drinking
both. A business school student is chosen at random. If the student is drinking beer,
what is the probability that he or she is also drinking mixed drinks?
A. 2/5
B. 4/7
C. 10/17
D. 7/24
E. 7/10

I didn't understand what the question asked :wall . I tried to calculate but all mismatch. Please provide some explanations.

hi,
probability of an event = favorable outcomes / total outcomes
suppose there are 1000 students (1000 taken to simplify the calculations)
first year students = 40% of 1000 = 400
second year students = 60% of 1000 = 600

of first year students, 40% are drinking beer, 40% are drinking mixed drinks, and 20% are drinking both
=> the number is 40% of 400, 40% of 400 and 20% of 400 respectively
=> 160, 160, 80

of the second year students, 30% are drinking beer, 30% are drinking mixed drinks, and 20% are drinking both
=> the number is 30% of 600, 30% of 600 and 20% of 600 respectively
=> 180, 180, 120

total (both beer and mixed drinks) drinkers = 80 + 120 = 200
total beer drinkers = 160 + 180 = 340

required probability = 200/340 = 10/17
_________________

CHEERS
fivezero7

Director
Director
User avatar
Joined: 25 Aug 2007
Posts: 940
WE 1: 3.5 yrs IT
WE 2: 2.5 yrs Retail chain
Followers: 77

Kudos [?]: 1330 [0], given: 40

Re: A business school club, Friends of Foam, is throwing a party at a loca [#permalink]

Show Tags

New post 20 Apr 2010, 23:39
Bunuel and GurpeetSingh.

Thanks for your analysis. I am clear now whre I was wrong. Both of you provided great insights to this problem.
_________________

Want to improve your CR: http://gmatclub.com/forum/cr-methods-an-approach-to-find-the-best-answers-93146.html
Tricky Quant problems: http://gmatclub.com/forum/50-tricky-questions-92834.html
Important Grammer Fundamentals: http://gmatclub.com/forum/key-fundamentals-of-grammer-our-crucial-learnings-on-sc-93659.html

Manager
Manager
User avatar
Joined: 29 Jun 2010
Posts: 248
Schools: LBS, Oxford
Followers: 9

Kudos [?]: 44 [0], given: 12

A business school club, Friends of Foam, is throwing a party at a loca [#permalink]

Show Tags

New post 10 Jul 2011, 20:43
A business school club, Friends of Foam, is throwing a party at a local bar. Of the business school students at the bar, 40% are first year students and 60% are second year students. Of the first year students, 40% are drinking beer, 40% are drinking mixed drinks, and 20% are drinking both. Of the second year students, 30% are drinking beer, 30% are drinking mixed drinks, and 20% are drinking both. A business school student is chosen at random. If the student is drinking beer, what is the probability that he or she is also drinking mixed drinks?

A. 2/5
B. 4/7
C. 10/17
D. 7/24
E. 7/10
Current Student
avatar
Joined: 26 May 2005
Posts: 564
Followers: 18

Kudos [?]: 215 [0], given: 13

Re: A business school club, Friends of Foam, is throwing a party at a loca [#permalink]

Show Tags

New post 10 Jul 2011, 22:58
Alchemist1320 wrote:
A business school club, Friends of Foam, is throwing a party at a local bar. Of the business school students at the bar, 40% are first year students and 60% are second year students. Of the first year students, 40% are drinking beer, 40% are drinking mixed drinks, and 20% are drinking both. Of the second year students, 30% are drinking beer, 30% are drinking mixed drinks, and 20% are drinking both. A business school student is chosen at random. If the student is drinking beer, what is the probability that he or she is also drinking mixed drinks?

A. 2/5
B. 4/7
C. 10/17
D. 7/24
E. 7/10



Suppose there are 100 students

Group A : 40% = 40 students
40% drink beer = 16
40% mixed = 16
20% both = 8

Group B 60% = 60
30% beer= 18
30% mixed = 18
20% both= 12

now we need both ( beer + mixed = both)

probability = total beer drinker = 16+18 =34 and both = 20
thus 20/34 = 10/17
Hence C
Re: A business school club, Friends of Foam, is throwing a party at a loca   [#permalink] 10 Jul 2011, 22:58
    Similar topics Author Replies Last post
Similar
Topics:
Anthony, Brad, and Cris are inviting 2 friends each to a party. If Ant SajjadAhmad 1 07 May 2017, 12:40
2 Experts publish their posts in the topic A group of 20 friends formed an investment club azamaka 2 11 Sep 2016, 18:57
2 Experts publish their posts in the topic A book club rented the party room of a local restaurant to meet and Bunuel 5 04 Feb 2016, 02:35
Experts publish their posts in the topic Joey is planning to throw a small party PrepTap 1 22 Apr 2015, 09:13
10 Experts publish their posts in the topic A foreign language club at Washington Middle School consists sivasanjeev 4 25 Feb 2016, 17:20
Display posts from previous: Sort by

A business school club, Friends of Foam, is throwing a party at a loca

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


GMAT Club MBA Forum Home| About| 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®.