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

 It is currently 25 May 2015, 18:30

# Today:

Free Access to GMAT Club Tests - May 25th for Memorial Day!!

### 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

# Events & Promotions

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

# Workers are grouped by their areas of expertise, and are

 Question banks Downloads My Bookmarks Reviews Important topics
Author Message
TAGS:
Senior Manager
Joined: 21 Jul 2009
Posts: 366
Schools: LBS, INSEAD, IMD, ISB - Anything with just 1 yr program.
Followers: 15

Kudos [?]: 113 [1] , given: 22

Workers are grouped by their areas of expertise, and are [#permalink]  08 Feb 2010, 20:44
1
This post received
KUDOS
3
This post was
BOOKMARKED
00:00

Difficulty:

(N/A)

Question Stats:

78% (02:07) correct 22% (01:43) wrong based on 14 sessions
Workers are grouped by their areas of expertise, and are placed on at least one team. 20 are on the marketing team, 30 are on the Sales team, and 40 are on the Vision team. 5 workers are on both the Marketing and Sales teams, 6 workers are on both the Sales and Vision teams, 9 workers are on both the Marketing and Vision teams, and 4 workers are on all three teams. How many workers are there in total?
_________________

I am AWESOME and it's gonna be LEGENDARY!!!

Math Expert
Joined: 02 Sep 2009
Posts: 27494
Followers: 4312

Kudos [?]: 42310 [0], given: 6012

Re: Union of three sets formula derivation? [#permalink]  09 Feb 2010, 17:10
Expert's post
Workers are grouped by their areas of expertise, and are placed on at least one team. 20 are on the marketing team, 30 are on the Sales team, and 40 are on the Vision team. 5 workers are on both the Marketing and Sales teams, 6 workers are on both the Sales and Vision teams, 9 workers are on both the Marketing and Vision teams, and 4 workers are on all three teams. How many workers are there in total?

Translating:
"are placed on at least one team": members of none =0;
"20 are on the marketing team": M=20;
"30 are on the Sales team": S=30;
"40 are on the Vision team": V=40;
"5 workers are on both the Marketing and Sales teams": MnS=5, note here that some from these 5 can be the members of Vision team as well, MnS is sections d an g on the diagram (assuming Marketing = A, Sales = B and Vision = C);
"6 workers are on both the Sales and Vision teams": SnV=6 (the same as above sections f an g);
"9 workers are on both the Marketing and Vision teams": MnV=9.
"4 workers are on all three teams": MnSnV=4, section 4.

Question: Total=?

Applying first formula as we have intersections of two groups and not the number of only (exactly) 2 group members:

$$Total=M+S+V-(MnS+MnV+SnV)+MnSnV+Neither=20+30+40-(5+6+9)+4+0=74$$.

Answer: 74.

For more check ADVANCED OVERLAPPING SETS PROBLEMS
_________________
Intern
Joined: 17 Sep 2012
Posts: 1
Followers: 0

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

Re: Workers are grouped by their areas of expertise, and are [#permalink]  27 Dec 2012, 05:31
I have a question. If the formula is:

Total = Group1 + Group2 + Group3 - (sum of 2-group overlaps) - 2*(all three) + Neither

why is it then + 4 instead of -2*4?
Math Expert
Joined: 02 Sep 2009
Posts: 27494
Followers: 4312

Kudos [?]: 42310 [0], given: 6012

Re: Workers are grouped by their areas of expertise, and are [#permalink]  27 Dec 2012, 05:38
Expert's post
alexjoh89 wrote:
I have a question. If the formula is:

Total = Group1 + Group2 + Group3 - (sum of 2-group overlaps) - 2*(all three) + Neither

why is it then + 4 instead of -2*4?

There are two formulas for 3 overlapping sets:
$$Total = A + B + C - (sum \ of \ 2-group \ overlaps) + (all \ three) + Neither$$.

$$Total = A + B + C - (sum \ of \ EXACTLY \ 2-group \ overlaps) - 2*(all \ three) + Neither$$.

For more check here: ADVANCED OVERLAPPING SETS PROBLEMS
_________________
Intern
Joined: 29 May 2013
Posts: 1
Followers: 0

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

Re: Workers are grouped by their areas of expertise, and are [#permalink]  27 Jun 2013, 11:49
Can you give an example of a problem where you would know to use the 2nd equation? Would the problem say something like "5 workers are in Marketing and Sales but not Vision, 4 are in Sales and Vision but not marketing," etc., so you know that each number does not include members that belong to all three sets?
Math Expert
Joined: 02 Sep 2009
Posts: 27494
Followers: 4312

Kudos [?]: 42310 [1] , given: 6012

Re: Workers are grouped by their areas of expertise, and are [#permalink]  27 Jun 2013, 11:54
1
This post received
KUDOS
Expert's post
elc280 wrote:
Can you give an example of a problem where you would know to use the 2nd equation? Would the problem say something like "5 workers are in Marketing and Sales but not Vision, 4 are in Sales and Vision but not marketing," etc., so you know that each number does not include members that belong to all three sets?

All examples are here: ADVANCED OVERLAPPING SETS PROBLEMS

DS questions on Overlapping Sets: search.php?search_id=tag&tag_id=45
PS questions on Overlapping Sets: search.php?search_id=tag&tag_id=65

Hope it helps.
_________________
SVP
Status: The Best Or Nothing
Joined: 27 Dec 2012
Posts: 1858
Location: India
Concentration: General Management, Technology
WE: Information Technology (Computer Software)
Followers: 22

Kudos [?]: 896 [1] , given: 193

Re: Workers are grouped by their areas of expertise, and are [#permalink]  15 Oct 2013, 01:22
1
This post received
KUDOS
Solved using Venn diagram attached:
Answer = 40 + 11 + 23 = 74
Attachments

vein.JPG [ 16.98 KiB | Viewed 5455 times ]

_________________

Kindly press "+1 Kudos" to appreciate

Intern
Joined: 26 May 2013
Posts: 2
Followers: 0

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

formula or venn diagram? [#permalink]  10 Dec 2013, 02:22
Workers are grouped by their areas of expertise and are placed on at least one

team. There are 20 workers on the Marketing team, 30 on the Sales team, and 40

on the Vision team. 5 workers are on both the Marketing and Sales teams, 6 workers

are on both the Sales and Vision teams, 9 workers are on both the Marketing

and Vision teams, and 4 workers are on all three teams. How many workers are

there in total?

How do you solve it using the formula:(Total in Group 1) + (Total in Group 2) + (Total in Group 3) – (Overlap of 1 and 2) – (Overlap of 1 and 3) – (Overlap of 2 and 3) – [2 * (Overlap of 1, 2, and 3)] + (total in none of the groups) = Overall total
Math Expert
Joined: 02 Sep 2009
Posts: 27494
Followers: 4312

Kudos [?]: 42310 [0], given: 6012

Re: formula or venn diagram? [#permalink]  10 Dec 2013, 03:30
Expert's post
dobrecf wrote:
Workers are grouped by their areas of expertise and are placed on at least one

team. There are 20 workers on the Marketing team, 30 on the Sales team, and 40

on the Vision team. 5 workers are on both the Marketing and Sales teams, 6 workers

are on both the Sales and Vision teams, 9 workers are on both the Marketing

and Vision teams, and 4 workers are on all three teams. How many workers are

there in total?

How do you solve it using the formula:(Total in Group 1) + (Total in Group 2) + (Total in Group 3) – (Overlap of 1 and 2) – (Overlap of 1 and 3) – (Overlap of 2 and 3) – [2 * (Overlap of 1, 2, and 3)] + (total in none of the groups) = Overall total

Merging similar topics. Please refer to the solutions above.

Also, please read carefully and follow: rules-for-posting-please-read-this-before-posting-133935.html Pay attention to rules, 1, 2, 3, 7, 8, and 10. Thank you.
_________________
Intern
Joined: 14 Jun 2011
Posts: 1
Followers: 0

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

Re: Workers are grouped by their areas of expertise, and are [#permalink]  11 Dec 2013, 10:43
Hi, unfortunately i got 62 in total as answer. Would anyone plz explain in which case i've made wrong? For your kind reference, i'm uploading the image of my solution.
Attachment:

Problem.jpg [ 31.12 KiB | Viewed 4545 times ]
Math Expert
Joined: 02 Sep 2009
Posts: 27494
Followers: 4312

Kudos [?]: 42310 [0], given: 6012

Re: Workers are grouped by their areas of expertise, and are [#permalink]  12 Dec 2013, 01:09
Expert's post
mn420 wrote:
Hi, unfortunately i got 62 in total as answer. Would anyone plz explain in which case i've made wrong? For your kind reference, i'm uploading the image of my solution.
Attachment:
Problem.jpg

Solving with formula: workers-are-grouped-by-their-areas-of-expertise-and-are-90246.html#p685690
Solving with Venn diagram: workers-are-grouped-by-their-areas-of-expertise-and-are-90246.html#p1278507

Hope this helps.
_________________
Manager
Joined: 20 Oct 2013
Posts: 66
Followers: 0

Kudos [?]: 0 [0], given: 27

Re: Workers are grouped by their areas of expertise, and are [#permalink]  29 Apr 2014, 10:06
Hi

How to identify when the qs is meaning to say exactly 2 overlaps and when the qs means otherwise? This qs seemed like it meant exactly 2.
_________________

Hope to clear it this time!!
GMAT 1: 540
Preparing again

Veritas Prep GMAT Instructor
Joined: 16 Oct 2010
Posts: 5548
Location: Pune, India
Followers: 1372

Kudos [?]: 6981 [2] , given: 178

Re: Workers are grouped by their areas of expertise, and are [#permalink]  29 Apr 2014, 22:26
2
This post received
KUDOS
Expert's post
nandinigaur wrote:
Hi

How to identify when the qs is meaning to say exactly 2 overlaps and when the qs means otherwise? This qs seemed like it meant exactly 2.

The question will have words such as 'only' or 'exactly' when it wants to specify that n number of people are in exactly 2 teams.
10 people belong to A and B implies that there are 10 people who belong to both. Some of them could belong to another set C too but that information is not available. All we know is that 10 belong to both A and B.
_________________

Karishma
Veritas Prep | GMAT Instructor
My Blog

Get started with Veritas Prep GMAT On Demand for $199 Veritas Prep Reviews Senior Manager Joined: 28 Apr 2014 Posts: 291 Followers: 0 Kudos [?]: 26 [0], given: 46 Re: Workers are grouped by their areas of expertise, and are [#permalink] 05 May 2014, 19:55 VeritasPrepKarishma wrote: nandinigaur wrote: Hi How to identify when the qs is meaning to say exactly 2 overlaps and when the qs means otherwise? This qs seemed like it meant exactly 2. The question will have words such as 'only' or 'exactly' when it wants to specify that n number of people are in exactly 2 teams. 10 people belong to A and B implies that there are 10 people who belong to both. Some of them could belong to another set C too but that information is not available. All we know is that 10 belong to both A and B. Thanks Karishma .. This was confusing me as well. Manager Joined: 20 Oct 2013 Posts: 66 Followers: 0 Kudos [?]: 0 [0], given: 27 Re: Workers are grouped by their areas of expertise, and are [#permalink] 06 May 2014, 04:13 VeritasPrepKarishma wrote: nandinigaur wrote: Hi How to identify when the qs is meaning to say exactly 2 overlaps and when the qs means otherwise? This qs seemed like it meant exactly 2. The question will have words such as 'only' or 'exactly' when it wants to specify that n number of people are in exactly 2 teams. 10 people belong to A and B implies that there are 10 people who belong to both. Some of them could belong to another set C too but that information is not available. All we know is that 10 belong to both A and B. Dear Karishma I thought i understood but then i saw the following qs: In a consumer survey, 85% of those surveyed liked at least one of three products: 1, 2, and 3. 50% of those asked liked product 1, 30% liked product 2, and 20% liked product 3. If 5% of the people in the survey liked all three of the products, what percentage of the survey participants liked more than one of the three products? in this how to know that we r being asked: people in exactly 2 grps + people in exactly 3 grps... no word is mentioned.... _________________ Hope to clear it this time!! GMAT 1: 540 Preparing again Math Expert Joined: 02 Sep 2009 Posts: 27494 Followers: 4312 Kudos [?]: 42310 [0], given: 6012 Re: Workers are grouped by their areas of expertise, and are [#permalink] 06 May 2014, 07:39 Expert's post nandinigaur wrote: VeritasPrepKarishma wrote: nandinigaur wrote: Hi How to identify when the qs is meaning to say exactly 2 overlaps and when the qs means otherwise? This qs seemed like it meant exactly 2. The question will have words such as 'only' or 'exactly' when it wants to specify that n number of people are in exactly 2 teams. 10 people belong to A and B implies that there are 10 people who belong to both. Some of them could belong to another set C too but that information is not available. All we know is that 10 belong to both A and B. Dear Karishma I thought i understood but then i saw the following qs: In a consumer survey, 85% of those surveyed liked at least one of three products: 1, 2, and 3. 50% of those asked liked product 1, 30% liked product 2, and 20% liked product 3. If 5% of the people in the survey liked all three of the products, what percentage of the survey participants liked more than one of the three products? in this how to know that we r being asked: people in exactly 2 grps + people in exactly 3 grps... no word is mentioned.... This question is discussed here: in-a-consumer-survey-85-of-those-surveyed-liked-at-least-98018.html Hope it helps. _________________ Veritas Prep GMAT Instructor Joined: 16 Oct 2010 Posts: 5548 Location: Pune, India Followers: 1372 Kudos [?]: 6981 [0], given: 178 Re: Workers are grouped by their areas of expertise, and are [#permalink] 06 May 2014, 22:26 Expert's post nandinigaur wrote: I thought i understood but then i saw the following qs: In a consumer survey, 85% of those surveyed liked at least one of three products: 1, 2, and 3. 50% of those asked liked product 1, 30% liked product 2, and 20% liked product 3. If 5% of the people in the survey liked all three of the products, what percentage of the survey participants liked more than one of the three products? in this how to know that we r being asked: people in exactly 2 grps + people in exactly 3 grps... no word is mentioned.... If the question wants to tell you the number of people who like 2 products but not all 3, it will say "30% people liked exactly two products." Or "52% people liked only one of these products" when it wants to tell you that 52% people liked just a single product and did not like other two products and so on... In this particular question, you are asked to find the number of people who liked more than one of the three products. This means you want the number of people who liked either 2 of the 3 products or all three products. So you are looking for "people in exactly 2 grps + people in exactly 3 grps". Note that you can calculate this in two ways: Method 1: people in exactly 2 grps + people in exactly 3 grps Method 2: people in 2 grps (including those in all three groups too) - 2* people in 3 grps (because they have been counted 3 times while counting people in 2 groups) Check out this post for more on three overlapping sets: http://www.veritasprep.com/blog/2012/09 ... ping-sets/ _________________ Karishma Veritas Prep | GMAT Instructor My Blog Get started with Veritas Prep GMAT On Demand for$199

Veritas Prep Reviews

Intern
Joined: 28 Dec 2013
Posts: 37
Followers: 0

Kudos [?]: 1 [0], given: 3

Workers are grouped by their areas of expertise, and are [#permalink]  25 Jun 2014, 09:16
[quote="Bunuel"]Workers are grouped by their areas of expertise, and are placed on at least one team. 20 are on the marketing team, 30 are on the Sales team, and 40 are on the Vision team. 5 workers are on both the Marketing and Sales teams, 6 workers are on both the Sales and Vision teams, 9 workers are on both the Marketing and Vision teams, and 4 workers are on all three teams. How many workers are there in total?

Translating:
"are placed on at least one team": members of none =0;
"20 are on the marketing team": M=20;
"30 are on the Sales team": S=30;
"40 are on the Vision team": V=40;
"5 workers are on both the Marketing and Sales teams": MnS=5, note here that some from these 5 can be the members of Vision team as well, MnS is sections d an g on the diagram (assuming Marketing = A, Sales = B and Vision = C);
"6 workers are on both the Sales and Vision teams": SnV=6 (the same as above sections f an g);
"9 workers are on both the Marketing and Vision teams": MnV=9.
"4 workers are on all three teams": MnSnV=4, section 4.

Question: Total=?

Applying first formula as we have intersections of two groups and not the number of only (exactly) 2 group members:

$$Total=M+S+V-(MnS+MnV+SnV)+MnSnV+Neither=20+30+40-(5+6+9)+4+0=74$$.

Answer: 74.

Why are we adding (5+6+9) when the formula has subtraction in it : (sum of exactly 2 - group overlaps) ?

Thanks
Math Expert
Joined: 02 Sep 2009
Posts: 27494
Followers: 4312

Kudos [?]: 42310 [0], given: 6012

Re: Workers are grouped by their areas of expertise, and are [#permalink]  25 Jun 2014, 09:19
Expert's post
sagnik242 wrote:
Bunuel wrote:
Workers are grouped by their areas of expertise, and are placed on at least one team. 20 are on the marketing team, 30 are on the Sales team, and 40 are on the Vision team. 5 workers are on both the Marketing and Sales teams, 6 workers are on both the Sales and Vision teams, 9 workers are on both the Marketing and Vision teams, and 4 workers are on all three teams. How many workers are there in total?

Translating:
"are placed on at least one team": members of none =0;
"20 are on the marketing team": M=20;
"30 are on the Sales team": S=30;
"40 are on the Vision team": V=40;
"5 workers are on both the Marketing and Sales teams": MnS=5, note here that some from these 5 can be the members of Vision team as well, MnS is sections d an g on the diagram (assuming Marketing = A, Sales = B and Vision = C);
"6 workers are on both the Sales and Vision teams": SnV=6 (the same as above sections f an g);
"9 workers are on both the Marketing and Vision teams": MnV=9.
"4 workers are on all three teams": MnSnV=4, section 4.

Question: Total=?

Applying first formula as we have intersections of two groups and not the number of only (exactly) 2 group members:

$$Total=M+S+V-(MnS+MnV+SnV)+MnSnV+Neither=20+30+40-(5+6+9)+4+0=74$$.

Answer: 74.

Why are we adding (5+6+9) when the formula has subtraction in it : (sum of exactly 2 - group overlaps) ?

Thanks

Because MnS+MnV+SnV gives 2-group overlaps.
_________________
Intern
Joined: 22 Feb 2014
Posts: 31
Followers: 0

Kudos [?]: 4 [0], given: 14

Re: Workers are grouped by their areas of expertise, and are [#permalink]  09 Jul 2014, 07:58
Bunuel wrote:
alexjoh89 wrote:
I have a question. If the formula is:

Total = Group1 + Group2 + Group3 - (sum of 2-group overlaps) - 2*(all three) + Neither

why is it then + 4 instead of -2*4?

There are two formulas for 3 overlapping sets:
$$Total = A + B + C - (sum \ of \ 2-group \ overlaps) + (all \ three) + Neither$$.

$$Total = A + B + C - (sum \ of \ EXACTLY \ 2-group \ overlaps) - 2*(all \ three) + Neither$$.

For more check here: ADVANCED OVERLAPPING SETS PROBLEMS

If I use second formula answer comes different.. Am i making any mistake?? Please correct

20+30+40- (20)- 2(4)+0
90-28 = 62

pLEASE aDVICE...are these two formulas suppose to give same answer right???
Re: Workers are grouped by their areas of expertise, and are   [#permalink] 09 Jul 2014, 07:58

Go to page    1   2    Next  [ 22 posts ]

Similar topics Replies Last post
Similar
Topics:
1 Study Group in SF Bay area 1 17 Feb 2014, 14:11
Study group in De/ Philly area 0 04 Jul 2013, 09:46
3 Workers are grouped by their areas of expertise and are plac 11 28 Sep 2011, 21:37
RE: GMAT Study Group in Phoenix/Surprise Area 1 14 Sep 2011, 19:18
GMAT group study.. Manhattan, NY area 0 22 Dec 2010, 21:17
Display posts from previous: Sort by

# Workers are grouped by their areas of expertise, and are

 Question banks Downloads My Bookmarks Reviews Important topics

 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®.