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

 It is currently 22 Oct 2016, 04:50

### 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

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

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# The attendees at a certain convention purchased a total of 15,000 book

Author Message
TAGS:

### Hide Tags

Intern
Joined: 31 May 2006
Posts: 44
Followers: 0

Kudos [?]: 11 [1] , given: 0

The attendees at a certain convention purchased a total of 15,000 book [#permalink]

### Show Tags

23 Jul 2006, 16:59
1
KUDOS
5
This post was
BOOKMARKED
00:00

Difficulty:

15% (low)

Question Stats:

75% (02:05) correct 25% (00:49) wrong based on 175 sessions

### HideShow timer Statistics

The attendees at a certain convention purchased a total of 15,000 books. How many of these attendees were female?

(1) There was a total of 4,000 attendees at the convention.
(2) The male attendees purchased an average (arithmetic mean) of 3 books each, and the female attendees purchased an average of 5 books each.
[Reveal] Spoiler: OA

Last edited by Bunuel on 20 Oct 2014, 08:32, edited 1 time in total.
Renamed the topic, edited the question, added the OA and moved to DS forum.
Manager
Joined: 21 Jul 2006
Posts: 83
Followers: 1

Kudos [?]: 21 [0], given: 0

Re: The attendees at a certain convention purchased a total of 15,000 book [#permalink]

### Show Tags

23 Jul 2006, 17:23
Form 1. 4000 = m + f
From 2. 15000 = 3m + 5f
using both solve for f

Thanks
VP
Joined: 07 Nov 2005
Posts: 1131
Location: India
Followers: 5

Kudos [?]: 41 [0], given: 1

Re: The attendees at a certain convention purchased a total of 15,000 book [#permalink]

### Show Tags

23 Jul 2006, 21:42
C it is.

Statement 1....... M + F = 4000,
Statement 2.......3M + 5F = 15000,

Solving => F = 1500.
_________________

Trying hard to conquer Quant.

GMAT Club Legend
Joined: 07 Jul 2004
Posts: 5062
Location: Singapore
Followers: 30

Kudos [?]: 337 [1] , given: 0

Re: The attendees at a certain convention purchased a total of 15,000 book [#permalink]

### Show Tags

23 Jul 2006, 22:20
1
KUDOS
1
This post was
BOOKMARKED
St1:
# of male attendees = m
# of female attendees = 4000-m

But we can't work further. Insufficient.

St2:
3m + 5f = 15,000

Can't solve as there are many possibilites for (m,f) sets

Using St1 and St2:
3m + 5(4000-m) = 15,000

Can solve for m, and thus f. Sufficient.

ANS c
Director
Joined: 28 Dec 2005
Posts: 755
Followers: 1

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

Re: The attendees at a certain convention purchased a total of 15,000 book [#permalink]

### Show Tags

24 Jul 2006, 00:46
shehreenquayyum wrote:
Attendees at a certain convention purchased 15000 boks. How many of these attendees are females?

i) Total attendees are 4000
ii) Males purchased an average of 3 books each & females purchased an average of 5 books each.

I think we have to use the weighted average? Answer is C....

Straight C

from 1: m+f =4000
from 2: 3m+5f=15000

2 equations and 2 unknowns, 1 and 2 are insuff. but combined can give the answer.
SVP
Joined: 30 Mar 2006
Posts: 1737
Followers: 1

Kudos [?]: 75 [0], given: 0

Re: The attendees at a certain convention purchased a total of 15,000 book [#permalink]

### Show Tags

25 Jul 2006, 04:40
C

1) M + F = 4000
Not Suff

2) 3M +5F = 15000
Not Suff

Together

3(4000-F) + 5F = 15000
12000 -3F +5F = 15000
2F = 3000
F = 1500
Manager
Joined: 27 Sep 2006
Posts: 70
Followers: 1

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

The attendees at a certain convention purchased a total of 15,000 [#permalink]

### Show Tags

28 Jan 2007, 00:44
2
This post was
BOOKMARKED
The attendees at a certain convention purchased a total of 15,000 books. How many of these attendees were female?

(1) There was a total of 4,000 attendees at the convention.
(2) The male attendees purchased an average (arithmetic mean) of 3 books each, and the female attendees purchased an average of 5 books each.

Last edited by Bunuel on 28 Sep 2014, 11:33, edited 1 time in total.
Renamed the topic, edited the question and added the OA.
SVP
Joined: 05 Jul 2006
Posts: 1574
Followers: 6

Kudos [?]: 276 [0], given: 42

Re: The attendees at a certain convention purchased a total of 15,000 [#permalink]

### Show Tags

28 Jan 2007, 03:01
Total attendees at a convention purchased 15000 books. How many of these were female?

1. 4000 attended the convention
2. On average men bought 3 books, females bought 5 books

My solution: 5/8 * 4000 = 2500 women. Is this correct? (even though we don't have to solve in DS). Thanks!

ONE IS OBVIOUSLY NOT SUFF

FROM TWO .......NOT SUFF

BOTH TOGETHER

TOTAL NUMBER OF BOOKS MEN PURCHASED/ TOTAL NMBER OF MEN = 3

X/Y =3

TOTAL NMBE OF BOOKS PURCHASED BY WOMEN/ NUMBER OF WOMEN =5

15000 - X / 4000- Y = 5

WE HAVE TWO EQUATIONS FOR TWO UNKNOWNS

3Y =X

15000 - 3Y = 20000 - 5Y

2Y = 5000 IE: Y = 2500 THUS ............SUFF

Director
Joined: 10 Oct 2005
Posts: 720
Followers: 3

Kudos [?]: 21 [1] , given: 0

Re: The attendees at a certain convention purchased a total of 15,000 [#permalink]

### Show Tags

28 Jan 2007, 23:57
1
KUDOS
successstory wrote:
Total attendees at a convention purchased 15000 books. How many of these were female?

1. 4000 attended the convention
2. On average men bought 3 books, females bought 5 books

My solution: 5/8 * 4000 = 2500 women. Is this correct? try to check by back solving females bought 2500*5=12500 books hence 2500 books was bought by men 2500/3=not integer and obviously can't be the number of men))) (even though we don't have to solve in DS). Thanks!

agree with yezz 1st and 2 statements insuff alone
taking both together
M+F=4000 -->M=4000-F
M*3+F*5=15000-->
3*(4000-F)+5F=15000
12000-3F+5F=15000
2F=3000
F=1500
M=2500
_________________

IE IMBA 2010

GMAT Club Legend
Joined: 09 Sep 2013
Posts: 12173
Followers: 538

Kudos [?]: 151 [0], given: 0

Re: The attendees at a certain convention purchased a total of 15,000 [#permalink]

### Show Tags

28 Sep 2014, 10:57
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.
_________________
Current Student
Joined: 26 Aug 2014
Posts: 827
Concentration: Marketing
GMAT 1: 680 Q V
GPA: 3.4
Followers: 7

Kudos [?]: 159 [0], given: 98

Re: The attendees at a certain convention purchased a total of 15,000 book [#permalink]

### Show Tags

19 Oct 2014, 16:50
can someone tell me why this reasoning is wrong.

For statement B - say you take it to mean for every 8 books, 5 are bought for 1 female. So for the 15,000 books 9375 are bought by females. Average out 5 books to one female and you have 1875 females.

Where is my logic going astray?
Veritas Prep GMAT Instructor
Joined: 16 Oct 2010
Posts: 6962
Location: Pune, India
Followers: 2024

Kudos [?]: 12717 [0], given: 221

Re: The attendees at a certain convention purchased a total of 15,000 book [#permalink]

### Show Tags

19 Oct 2014, 20:47
angelfire213 wrote:
can someone tell me why this reasoning is wrong.

For statement B - say you take it to mean for every 8 books, 5 are bought for 1 female. So for the 15,000 books 9375 are bought by females. Average out 5 books to one female and you have 1875 females.

Where is my logic going astray?

You are assuming that number of males = number of females which is not given.
You say that one male and one female buy a total of 8 books so total number of pairs = 15000/8 = 1875. So we get that there are 1875 males and 1875 females.

But isn't this possible - there are 3 females who buy 15 books and rest 14985 books are bought by 4995 males? This will give us a total of 15000 books bought such that on average males buy 3 books per person and females buy 5 books per person.

Similarly, there are many other cases possible.

This question can be done by weighted averages concept (discussed here: http://www.veritasprep.com/blog/2011/03 ... -averages/) in seconds.

We know w1/w2 = (A2 - Aavg)/(Aavg - A1)
We need to find the fraction w1/w2 = Number of males/Number of females and the total number of people to get the number of females.

i) Total attendees are 4000
This gives us Aavg = 15000/4000
We also get that w1 + w2 = 4000.
But we don't have A1, A2.

ii) Males purchased an average of 3 books each & females purchased an average of 5 books each.
This gives us A1 = 3 and A2 = 5
We don't have Aavg.

Using both, we have Aavg, A1 and A2. So we can find w1/w2 and we also know that total number of people is 4000. This is sufficient to answer the question.

_________________

Karishma
Veritas Prep | GMAT Instructor
My Blog

Get started with Veritas Prep GMAT On Demand for \$199

Veritas Prep Reviews

GMAT Club Legend
Joined: 09 Sep 2013
Posts: 12173
Followers: 538

Kudos [?]: 151 [0], given: 0

Re: The attendees at a certain convention purchased a total of 15,000 book [#permalink]

### Show Tags

09 Mar 2016, 08:22
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.
_________________
Re: The attendees at a certain convention purchased a total of 15,000 book   [#permalink] 09 Mar 2016, 08:22
Similar topics Replies Last post
Similar
Topics:
To attend a conference, each attendee booked a reservation at a partic 1 12 Sep 2016, 03:46
3 If a certain charity collected a total of 360 books, videos 8 16 Apr 2012, 09:37
26 Store S sold a total of 90 copies of a certain book during 18 06 Dec 2009, 10:40
6 Store S sold a total of 90 copies of a certain book during 3 27 Oct 2009, 05:10
A total of 100 customers purchased books at a certain bookstore last 20 12 Sep 2008, 10:14
Display posts from previous: Sort by