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.

It appears that you are browsing the GMAT Club forum unregistered!

Signing up is free, quick, and confidential.
Join other 500,000 members and get the full benefits of GMAT Club

Registration gives you:

Tests

Take 11 tests and quizzes from GMAT Club and leading GMAT prep companies such as Manhattan GMAT,
Knewton, and others. All are free for GMAT Club members.

Applicant Stats

View detailed applicant stats such as GPA, GMAT score, work experience, location, application
status, and more

Books/Downloads

Download thousands of study notes,
question collections, GMAT Club’s
Grammar and Math books.
All are free!

Thank you for using the timer!
We noticed you are actually not timing your practice. Click the START button first next time you use the timer.
There are many benefits to timing your practice, including:

Of the 84 parents who attended a meeting at a school, 35 [#permalink]

Show Tags

24 Mar 2011, 22:10

4

This post was BOOKMARKED

00:00

A

B

C

D

E

Difficulty:

25% (medium)

Question Stats:

77% (02:56) correct
23% (01:55) wrong based on 421 sessions

HideShow timer Statistics

Of the 84 parents who attended a meeting at a school, 35 volunteered to supervise children during the school picnic and 11 volunteered both to supervise children during the picnic and to bring refreshments to the picnic.If the number of parents who volunteered to bring refreshments was 1.5 times the number of parents who neither volunteered to supervise children during the picnic nor volunteered to bring refreshments, how many of the parents volunteered to bring refreshments?

Re: is Double Set martix a good option to solve dis question [#permalink]

Show Tags

24 Mar 2011, 23:04

GMATD11 wrote:

14) of the 84 parents who attended a meeting at a school, 35 volunteered to supervise children during the school picnic and 11 volunteered both to supervise children during the picnic and to bring refreshments to the picnic.If the number of parents who volunteered to bring refreshments was 1.5 times the number of parents who neither volunteered to supervise children during the picnic nor volunteered to bring refreshments, how many of the parents volunteered to bring refreshments?

a) 25 b) 36 c) 38 d) 42 e) 45

Bring refreshment Volunteered Total to Supervise 11 35 Volunteered x=? y Total 11+x 35+y 84

11+x+35+y=84 x+y= 38 x=1.5y x=24

A

is dis the correct method to solve.

when to use double set matrix and when to use venn diagram for two type of information

Are you sure about the OA? I thinker the right answer should be 36. Here is how:

Total = Supervise + Refreshments + None - Both

We are given Total = 84, Supervise = 35, Both = 11 and Refreshments = 1.5*None

14) of the 84 parents who attended a meeting at a school, 35 volunteered to supervise children during the school picnic and 11 volunteered both to supervise children during the picnic and to bring refreshments to the picnic.If the number of parents who volunteered to bring refreshments was 1.5 times the number of parents who neither volunteered to supervise children during the picnic nor volunteered to bring refreshments, how many of the parents volunteered to bring refreshments?

a) 25 b) 36 c) 38 d) 42 e) 45

when to use double set matrix and when to use venn diagram for two type of information

Most GMAT questions can be easily and quickly solved using Venn Diagrams. (Different people prefer different strategies but I have found that no matter how tricky the question wording is, once you draw the Venn diagram, it all seems very clear)

Check out the Venn diagram for this question:

Attachment:

Ques2.jpg [ 13.38 KiB | Viewed 19037 times ]

Now, since it is given that x+11 = 1.5 (84-(24+11+x)) x = 25 So number of parents who volunteered to bring refreshments = x+11 = 25+11 = 36 _________________

Re: is Double Set martix a good option to solve dis question [#permalink]

Show Tags

13 Jun 2011, 07:56

2

This post received KUDOS

neither volunteered to supervise children during the picnic nor volunteered to bring refreshments = x number of parents volunteered to bring refreshments = 1.5x so, 84 = 35 + 1.5x - 11 + x 2.5x = 60 x = 24 Thus, number of parents volunteered to bring refreshments = 24*1.5=36 Ans. B _________________

Re: Of the 84 parents who attended a meeting at a school, 35 [#permalink]

Show Tags

25 Feb 2012, 22:13

Baten80 wrote:

neither volunteered to supervise children during the picnic nor volunteered to bring refreshments = x number of parents volunteered to bring refreshments = 1.5x so, 84 = 35 + 1.5x - 11 + x 2.5x = 60 x = 24 Thus, number of parents volunteered to bring refreshments = 24*1.5=36 Ans. B

Why isn't the overlap substracted also from the parents who bring refreshments?

When we are given 35 who volunteered to supervise, we substract the overlap (11), so total = 24; why isn't the final number of parents who voluntereed to refreshments = 1.5x - 11 ?

Of the 84 parents who attended a meeting at a school, 35 volunteered to supervise children during the school picnic and 11 volunteered both to supervise children during the picnic and to bring refreshments to the picnic.If the number of parents who volunteered to bring refreshments was 1.5 times the number of parents who neither volunteered to supervise children during the picnic nor volunteered to bring refreshments, how many of the parents volunteered to bring refreshments? A) 25 B) 36 C) 38 D) 42 E) 45

neither volunteered to supervise children during the picnic nor volunteered to bring refreshments = x number of parents volunteered to bring refreshments = 1.5x so, 84 = 35 + 1.5x - 11 + x 2.5x = 60 x = 24 Thus, number of parents volunteered to bring refreshments = 24*1.5=36 Ans. B

Why isn't the overlap substracted also from the parents who bring refreshments?

When we are given 35 who volunteered to supervise, we substract the overlap (11), so total = 24; why isn't the final number of parents who voluntereed to refreshments = 1.5x - 11 ?

84 = (35-11) + (1.5x - 11) + x

???

Because parents who supervise (1.5x) consist of the parent who supervise AND bring refreshments (11) and of the parents who supervise but DO NOT bring refreshments (1.5x-11). So if we subtract 11 (the parent who supervise AND bring refreshments) we'll get the parents who supervise but DO NOT bring refreshments and no the total parents who supervise.

Generally: {Total}={Supervise}+{Refreshments}-{Both}+{Neither} (notice that we subtract {Both} since it's already included twice: once in {Supervise} and once in {Refreshments});

Given: 84=35+1.5x-11+x --> x=24 --> 1.5x=36.

Answer: B.

Below matrix might help to understand the question better:

Attachment:

Parents.PNG [ 5.62 KiB | Viewed 17786 times ]

Notice that numbers in black are given and in red are calculated. We need the value of yellow box: 1.5x+(24+x)=84 --> x=24 --> 1.5x=36.

Re: Of the 84 parents who attended a meeting at a school, 35 [#permalink]

Show Tags

01 Dec 2012, 23:48

1

This post received KUDOS

You can use a chart to help you solve this problem as taught in the MGMAT.

= S stands for Supervise and ~S means not Supervise = R stands for Bring Refreshments and ~R means not Bring Refreshments

So how to use the chart? = Place in the rightmost corner the total of parents which is 84. = We know that there are 35 who volunteered to Supervise but since we do not know whether they are R or ~R, we put 35 at the bottom of column S. = We know that there are 11 who are both S and R. So we placed 11 accordingly. = We know those who are R is 1.5 times of those who are ~R and ~S. So we use a variable x to denote that relationship.

From the chart we can construct our equation clearly.

Re: Of the 84 parents who attended a meeting at a school, 35 [#permalink]

Show Tags

20 Mar 2013, 05:16

1

This post received KUDOS

The language used in these problems confuses me!! Example : 35 volunteered to supervise children during the school picnic ---> Only supervise + supervise & bring refreshments However, how many of the parents volunteered to bring refreshments --> This ideally should mean: supervise & bring refreshments + Only bring refreshment. But sadly the answer choice has value which = only bring refreshment Any suggestions on how to go about? _________________

The language used in these problems confuses me!! Example : 35 volunteered to supervise children during the school picnic ---> Only supervise + supervise & bring refreshments However, how many of the parents volunteered to bring refreshments --> This ideally should mean: supervise & bring refreshments + Only bring refreshment. But sadly the answer choice has value which = only bring refreshment Any suggestions on how to go about?

The language used in these problems confuses me!! Example : 35 volunteered to supervise children during the school picnic ---> Only supervise + supervise & bring refreshments However, how many of the parents volunteered to bring refreshments --> This ideally should mean: supervise & bring refreshments + Only bring refreshment. But sadly the answer choice has value which = only bring refreshment Any suggestions on how to go about?

You need to actively look for the word 'only' in these questions.

35 volunteered to supervise children: Overall, 35 people volunteered to supervise. This includes people who volunteered to do both - supervise and bring refreshments

35 volunteered to only supervise children: Does not include people who volunteered to do both.

How many of the parents volunteered to bring refreshments? Overall, how many volunteered to bring refreshments - it will include people who volunteered to do both. There is no ambiguity here.

How many of the parents volunteered to only bring refreshments? Now this is only refreshments.

Re-consider the calculations done above. _________________

Re: Of the 84 parents who attended a meeting at a school, 35 [#permalink]

Show Tags

20 Oct 2014, 19:44

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: Of the 84 parents who attended a meeting at a school, 35 [#permalink]

Show Tags

18 Jul 2015, 03:01

Hi,

I tried solving this problem exactly as per the method described.

Solving the equation that you have mentioned: x+11 = 1.5 (84-(24+11+x)) x +11 = 1.5 (84-24-11-x) x + 11 = 1.5 (49 - x) Solving for x gives x=29.4 Please help me understand this discrepancy.

VeritasPrepKarishma wrote:

GMATD11 wrote:

14) of the 84 parents who attended a meeting at a school, 35 volunteered to supervise children during the school picnic and 11 volunteered both to supervise children during the picnic and to bring refreshments to the picnic.If the number of parents who volunteered to bring refreshments was 1.5 times the number of parents who neither volunteered to supervise children during the picnic nor volunteered to bring refreshments, how many of the parents volunteered to bring refreshments?

a) 25 b) 36 c) 38 d) 42 e) 45

when to use double set matrix and when to use venn diagram for two type of information

Most GMAT questions can be easily and quickly solved using Venn Diagrams. (Different people prefer different strategies but I have found that no matter how tricky the question wording is, once you draw the Venn diagram, it all seems very clear)

Check out the Venn diagram for this question:

Attachment:

Ques2.jpg

Now, since it is given that x+11 = 1.5 (84-(24+11+x)) x = 25 So number of parents who volunteered to bring refreshments = x+11 = 25+11 = 36

Re: Of the 84 parents who attended a meeting at a school, 35 [#permalink]

Show Tags

08 Dec 2015, 11:53

GMATD11 wrote:

Of the 84 parents who attended a meeting at a school, 35 volunteered to supervise children during the school picnic and 11 volunteered both to supervise children during the picnic and to bring refreshments to the picnic.If the number of parents who volunteered to bring refreshments was 1.5 times the number of parents who neither volunteered to supervise children during the picnic nor volunteered to bring refreshments, how many of the parents volunteered to bring refreshments?

Again, unless ONLY is mentioned DO NOT ASSUME that 35 does not include 11 who volunteered to do both (supervise as well as bring refreshments). CRITICAL for such question types. _________________

KUDOS!!!, I need them too

gmatclubot

Re: Of the 84 parents who attended a meeting at a school, 35
[#permalink]
08 Dec 2015, 11:53

This is the kickoff for my 2016-2017 application season. After a summer of introspect and debate I have decided to relaunch my b-school application journey. Why would anyone want...

Check out this awesome article about Anderson on Poets Quants, http://poetsandquants.com/2015/01/02/uclas-anderson-school-morphs-into-a-friendly-tech-hub/ . Anderson is a great place! Sorry for the lack of updates recently. I...