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

It is currently 23 Oct 2014, 04:52

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

Each person attending a fund-raising party for a certain clu

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
Manager
Manager
User avatar
Joined: 06 Apr 2010
Posts: 144
Followers: 3

Kudos [?]: 113 [0], given: 15

Reviews Badge
Each person attending a fund-raising party for a certain clu [#permalink] New post 23 Sep 2010, 11:15
00:00
A
B
C
D
E

Difficulty:

  25% (medium)

Question Stats:

79% (01:50) correct 21% (00:44) wrong based on 53 sessions
Each person attending a fund-raising party for a certain club was charged the same admission fee. How many people attended the party?

(1) If the admission fee had been 0.75$ less and 100 more people had attended, the club would have received the same amount in admission fee
(2) If the admission fee had been 1.50$ less and 100 fewer people had attended, the club would have received the same amount in admission fee
[Reveal] Spoiler: OA

Attachments

Image7.JPG
Image7.JPG [ 13.33 KiB | Viewed 1858 times ]

Expert Post
2 KUDOS received
Math Expert
User avatar
Joined: 02 Sep 2009
Posts: 23393
Followers: 3609

Kudos [?]: 28825 [2] , given: 2852

Re: Club Admission Fee [#permalink] New post 23 Sep 2010, 12:02
2
This post received
KUDOS
Expert's post
Each person attending a fund raising party for a certain club was charged the same admission fee. How many people attended the party?

Let the original admission fee be x and the original # of people be n. Question: n=?

(1) If the admission fee had been 0.75$ less and 100 more people had attended, the club would have received the same amount in the admission fee

xn=(x-0.75)(n+100) --> 100x-0.75n=75. Two unknowns, one equation, not sufficient to calculate n.

(2 ) If the admission fee had been 1.50$ less and 100 fewer people had attended, the club would have received the same amount in the admission fee

xn=(x-1.5)(n-100) --> 100x-1.5n=-150. Two unknowns, one equation, not sufficient to calculate n.

(1)+(2) 100x-0.75n=75 and 100x-1.5n=-150 --> we have two distinct linear equation with two unknowns, hence we can solve for n. Sufficient.

Answer: C.
_________________

NEW TO MATH FORUM? PLEASE READ THIS: ALL YOU NEED FOR QUANT!!!

PLEASE READ AND FOLLOW: 11 Rules for Posting!!!

RESOURCES: [GMAT MATH BOOK]; 1. Triangles; 2. Polygons; 3. Coordinate Geometry; 4. Factorials; 5. Circles; 6. Number Theory; 7. Remainders; 8. Overlapping Sets; 9. PDF of Math Book; 10. Remainders; 11. GMAT Prep Software Analysis NEW!!!; 12. SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) NEW!!!; 12. Tricky questions from previous years. NEW!!!;

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?
25 extra-hard Quant Tests

Get the best GMAT Prep Resources with GMAT Club Premium Membership

Senior Manager
Senior Manager
avatar
Joined: 18 Sep 2009
Posts: 373
Followers: 3

Kudos [?]: 92 [0], given: 2

Re: Club Admission Fee [#permalink] New post 24 Sep 2010, 11:13
let assume x=admin fee,y=no.of. people
x*y=100.
1) (x-.75)* (y+100)= 100 (statement 1 mentioned same amount,so i assume the amount as 100)
from question stem x*y=100
so x=100/y, sufficient to know x value.

2) (x+1.50) * (y-100) =100
x*y =100
x=100/y,sufficient to know x value.

Bunnel, plz explain why should we solve the problem like this.
Manager
Manager
avatar
Joined: 04 Aug 2010
Posts: 158
Followers: 2

Kudos [?]: 24 [0], given: 15

Re: Club Admission Fee [#permalink] New post 24 Sep 2010, 14:17
TomB, how can you assign a random value (100) to xy and claim that x can be solved??

Let a = admission fee and n = number of people attended

(1) If the admission fee had been $0.75 less and 100 more people attended, the club would have received the same amount in admission fees.

an = (a - 0.75)(n + 100)
an = an - 0.75n + 100a -75
0.75n - 100a = -75

Insufficient

(2) If the admission fee had been $1.50 more and 100 fewer people had atteneded, the club would have received the same amount in admission fees.

an = (a + 1.50)(n - 100)
an = an + 1.5n - 100a - 150
1.5n - 100a = 150

Insufficent

Subtrace (1) from (2)
1.5n - 100a = 150
0.75n - 100a = -75

0.75n = 225 >> n = 300 & a can be solved
Intern
Intern
avatar
Joined: 29 Aug 2012
Posts: 10
Followers: 0

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

Each person attending a party was charged the same admission [#permalink] New post 09 Nov 2012, 06:28
Each person attending a party was charged the same admission fee. How many people attended the party?

(1) If the fee had been 0.75$ less and 100 more people had attended, the club would have made the same amount of money.
(2) If the fee had been 1.50$ more and 100 fewer people had attended, the club would have made the same amount of money.

I have a specific question regarding this problem :

Obviously Statement 1 and 2 are insufficient alone, however once we find out equation 1: xy = (x-3/4)(y+100) from statement 1 and xy = (x+3/2)(y-100) from statement 2, why can't we simply equate them?
(x-3/4)(y+100) = (x+3/2)(y-100)

I'd appreciate any help! Thanks

Last edited by Bunuel on 09 Nov 2012, 06:32, edited 1 time in total.
Renamed the topic and edited the question.
Expert Post
Math Expert
User avatar
Joined: 02 Sep 2009
Posts: 23393
Followers: 3609

Kudos [?]: 28825 [0], given: 2852

Re: Each person attending a party was charged the same admission [#permalink] New post 09 Nov 2012, 06:43
Expert's post
mockney wrote:
Each person attending a party was charged the same admission fee. How many people attended the party?

(1) If the fee had been 0.75$ less and 100 more people had attended, the club would have made the same amount of money.
(2) If the fee had been 1.50$ more and 100 fewer people had attended, the club would have made the same amount of money.

I have a specific question regarding this problem :

Obviously Statement 1 and 2 are insufficient alone, however once we find out equation 1: xy = (x-3/4)(y+100) from statement 1 and xy = (x+3/2)(y-100) from statement 2, why can't we simply equate them?
(x-3/4)(y+100) = (x+3/2)(y-100)

I'd appreciate any help! Thanks


Well, actually you can: (x-3/4)(y+100) = (x+3/2)(y-100) --> 9y=800x+300.

From xy = (x-3/4)(y+100) we'll have that 3y=400x-300, so 9y=1200x-900. Equating again: 800x+300=1200x-900 --> x=3 --> y=300.

Though you can directly simplify xy = (x-3/4)(y+100) to get 3y=400x-300 and xy = (x+3/2)(y-100) to get 3y=200x+300 --> 400x-300=200x+300 --> x=3 --> y=300.

Hope it's clear.
_________________

NEW TO MATH FORUM? PLEASE READ THIS: ALL YOU NEED FOR QUANT!!!

PLEASE READ AND FOLLOW: 11 Rules for Posting!!!

RESOURCES: [GMAT MATH BOOK]; 1. Triangles; 2. Polygons; 3. Coordinate Geometry; 4. Factorials; 5. Circles; 6. Number Theory; 7. Remainders; 8. Overlapping Sets; 9. PDF of Math Book; 10. Remainders; 11. GMAT Prep Software Analysis NEW!!!; 12. SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) NEW!!!; 12. Tricky questions from previous years. NEW!!!;

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?
25 extra-hard Quant Tests

Get the best GMAT Prep Resources with GMAT Club Premium Membership

Intern
Intern
avatar
Joined: 29 Aug 2012
Posts: 10
Followers: 0

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

Re: Each person attending a party was charged the same admission [#permalink] New post 09 Nov 2012, 06:54
Thank you Bunuel for your help!
I was just expecting to find a value for either x or y directly without needing to isolate for y from one of the 2 equations!
Senior Manager
Senior Manager
avatar
Joined: 08 Jun 2010
Posts: 454
Followers: 0

Kudos [?]: 30 [0], given: 39

Re: Each person attending a party was charged the same admission [#permalink] New post 15 Nov 2012, 02:41
WE NEed to show that the two equatin is not the same. but I do not know how to do. pls, help

we can avoid much computation.
Expert Post
Math Expert
User avatar
Joined: 02 Sep 2009
Posts: 23393
Followers: 3609

Kudos [?]: 28825 [0], given: 2852

Re: Each person attending a fund-raising party for a certain clu [#permalink] New post 14 Aug 2013, 01:41
Expert's post
Intern
Intern
avatar
Joined: 03 Dec 2013
Posts: 20
Location: Uzbekistan
Concentration: Finance, Entrepreneurship
GMAT 1: 610 Q47 V27
GRE 1: 600 Q790 V400
GPA: 3.4
WE: Analyst (Commercial Banking)
Followers: 0

Kudos [?]: 10 [0], given: 54

Premium Member CAT Tests
DS [#permalink] New post 25 Dec 2013, 22:18
If everyone was charged the same fee, how many people came to the club?


a. If the fee had been %0.75 less and 100 more people came the club would
have received the same amount.
b. If fee had been $1.50 more and 100 fewer people came, the club would
have received the same amount
Intern
Intern
avatar
Joined: 03 Dec 2013
Posts: 20
Location: Uzbekistan
Concentration: Finance, Entrepreneurship
GMAT 1: 610 Q47 V27
GRE 1: 600 Q790 V400
GPA: 3.4
WE: Analyst (Commercial Banking)
Followers: 0

Kudos [?]: 10 [0], given: 54

Premium Member CAT Tests
Re: DS [#permalink] New post 25 Dec 2013, 22:21
aja1991 wrote:
If everyone was charged the same fee, how many people came to the club?


a. If the fee had been %0.75 less and 100 more people came the club would
have received the same amount.
b. If fee had been $1.50 more and 100 fewer people came, the club would
have received the same amount




The official answer is C, but the solution is very complicated. So, please, can somebody over there help me to handle this problem?
Expert Post
Math Expert
User avatar
Joined: 02 Sep 2009
Posts: 23393
Followers: 3609

Kudos [?]: 28825 [0], given: 2852

Re: DS [#permalink] New post 26 Dec 2013, 02:05
Expert's post
aja1991 wrote:
If everyone was charged the same fee, how many people came to the club?


a. If the fee had been %0.75 less and 100 more people came the club would
have received the same amount.
b. If fee had been $1.50 more and 100 fewer people came, the club would
have received the same amount


Merging similar topics. Please refer to the solutions above.
_________________

NEW TO MATH FORUM? PLEASE READ THIS: ALL YOU NEED FOR QUANT!!!

PLEASE READ AND FOLLOW: 11 Rules for Posting!!!

RESOURCES: [GMAT MATH BOOK]; 1. Triangles; 2. Polygons; 3. Coordinate Geometry; 4. Factorials; 5. Circles; 6. Number Theory; 7. Remainders; 8. Overlapping Sets; 9. PDF of Math Book; 10. Remainders; 11. GMAT Prep Software Analysis NEW!!!; 12. SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) NEW!!!; 12. Tricky questions from previous years. NEW!!!;

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?
25 extra-hard Quant Tests

Get the best GMAT Prep Resources with GMAT Club Premium Membership

Intern
Intern
avatar
Joined: 03 Dec 2013
Posts: 20
Location: Uzbekistan
Concentration: Finance, Entrepreneurship
GMAT 1: 610 Q47 V27
GRE 1: 600 Q790 V400
GPA: 3.4
WE: Analyst (Commercial Banking)
Followers: 0

Kudos [?]: 10 [0], given: 54

Premium Member CAT Tests
Re: DS [#permalink] New post 26 Dec 2013, 02:42
Bunuel wrote:
aja1991 wrote:
If everyone was charged the same fee, how many people came to the club?


a. If the fee had been %0.75 less and 100 more people came the club would
have received the same amount.
b. If fee had been $1.50 more and 100 fewer people came, the club would
have received the same amount


Merging similar topics. Please refer to the solutions above.




Thanks. I found out why the problem was so confusing. There is a big difference between %0.75 and $0.75. I thought that 0.75 was a percentage increase which was wrong.
Re: DS   [#permalink] 26 Dec 2013, 02:42
    Similar topics Author Replies Last post
Similar
Topics:
Each person attending a party was charged the same admission mockney 0 15 Nov 2012, 02:41
Each person who attended a certain concert paid the same dreambeliever 9 02 Jun 2011, 18:35
Each person attending a fund raising party for a certain EnterMatrix 2 10 Jul 2010, 00:25
1 Each person attending a fund-raising party for a certain japped187 4 07 Mar 2008, 03:15
1 Experts publish their posts in the topic Each person attending a fund-raising party for a certain clu tarek99 8 11 Dec 2007, 14:48
Display posts from previous: Sort by

Each person attending a fund-raising party for a certain clu

  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®.