When Professor Wang looked at the rosters for this term's : GMAT Problem Solving (PS)
Check GMAT Club Decision Tracker for the Latest School Decision Releases http://gmatclub.com/AppTrack

 It is currently 24 Jan 2017, 10:33

### 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

# When Professor Wang looked at the rosters for this term's

Author Message
TAGS:

### Hide Tags

Intern
Joined: 24 Nov 2012
Posts: 12
Followers: 0

Kudos [?]: 18 [0], given: 0

When Professor Wang looked at the rosters for this term's [#permalink]

### Show Tags

27 Nov 2012, 00:20
4
This post was
BOOKMARKED
00:00

Difficulty:

25% (medium)

Question Stats:

68% (02:42) correct 32% (01:56) wrong based on 139 sessions

### HideShow timer Statistics

When Professor Wang looked at the rosters for this term's classes, she saw that the roster for her economics class (E) had 26 names, the roster for her marketing class (M) had 28, and the roster for her statistics class (S) had 18. When she compared the rosters, she saw that E and M had 9 names in common, E and S had 7, and M and S had 10. She also saw that 4 names were on all 3 rosters. If the rosters for Professor Wang's 3 classes are combined with no student's name listed more than once, how many names will be on the combined roster?

A. 30
B. 34
C. 42
D. 46
E. 50
[Reveal] Spoiler: OA

Last edited by Bunuel on 30 Sep 2014, 02:45, edited 2 times in total.
Renamed the topic and edited the tags.
Math Expert
Joined: 02 Sep 2009
Posts: 36638
Followers: 7106

Kudos [?]: 93653 [0], given: 10583

Re: When Professor Wang looked at the rosters for this term's [#permalink]

### Show Tags

27 Nov 2012, 02:48
saxenarahul021 wrote:
When Professor Wang looked at the rosters for this term's classes, she saw that the roster for her economics class (E) had 26 names, the roster for her marketing class (M) had 28, and the roster for her statistics class (S) had 18. When she compared the rosters, she saw that E and M had 9 names in common, E and S had 7, and M and S had 10. She also saw that 4 names were on all 3 rosters. If the rosters for Professor Wang's 3 classes are combined with no student's name listed more than once, how many names will be on the combined roster?

A. 30
B. 34
C. 42
D. 46
E. 50

Total # of students 26+28+18-(9+7+10)+4=50.

For more check ADVANCED OVERLAPPING SETS PROBLEMS
_________________
Manager
Joined: 26 Feb 2012
Posts: 116
Location: India
Concentration: General Management, Finance
WE: Engineering (Telecommunications)
Followers: 0

Kudos [?]: 19 [0], given: 56

Re: When Professor Wang looked at the rosters for this term's [#permalink]

### Show Tags

15 Jan 2014, 19:11
Bunuel wrote:
saxenarahul021 wrote:
When Professor Wang looked at the rosters for this term's classes, she saw that the roster for her economics class (E) had 26 names, the roster for her marketing class (M) had 28, and the roster for her statistics class (S) had 18. When she compared the rosters, she saw that E and M had 9 names in common, E and S had 7, and M and S had 10. She also saw that 4 names were on all 3 rosters. If the rosters for Professor Wang's 3 classes are combined with no student's name listed more than once, how many names will be on the combined roster?

A. 30
B. 34
C. 42
D. 46
E. 50

Total # of students 26+28+18-(9+7+10)+4=50.

For more check ADVANCED OVERLAPPING SETS PROBLEMS

Hi Bunuel
Lemme know why it is +4 rather than -4

Also please solve through ven-diagram actually my i got wrong while solving in ven diagram....

Rgds
Prasannajeet
Veritas Prep GMAT Instructor
Joined: 16 Oct 2010
Posts: 7132
Location: Pune, India
Followers: 2140

Kudos [?]: 13712 [1] , given: 222

Re: When Professor Wang looked at the rosters for this term's [#permalink]

### Show Tags

15 Jan 2014, 20:40
1
KUDOS
Expert's post
1
This post was
BOOKMARKED
prasannajeet wrote:
Bunuel wrote:
saxenarahul021 wrote:
When Professor Wang looked at the rosters for this term's classes, she saw that the roster for her economics class (E) had 26 names, the roster for her marketing class (M) had 28, and the roster for her statistics class (S) had 18. When she compared the rosters, she saw that E and M had 9 names in common, E and S had 7, and M and S had 10. She also saw that 4 names were on all 3 rosters. If the rosters for Professor Wang's 3 classes are combined with no student's name listed more than once, how many names will be on the combined roster?

A. 30
B. 34
C. 42
D. 46
E. 50

Total # of students 26+28+18-(9+7+10)+4=50.

For more check ADVANCED OVERLAPPING SETS PROBLEMS

Hi Bunuel
Lemme know why it is +4 rather than -4

Also please solve through ven-diagram actually my i got wrong while solving in ven diagram....

Rgds
Prasannajeet

When making the Venn diagram here, start by putting in the number of students which are in all 3 sets i.e. 4
Next, E and M had 9 names in common so the overlap of E and M excluding the overlap of all 3 will be 9 - 4 = 5.
Similarly for the E and S overlap and M and S overlap.
Next, E has 26 people and after removing 5 + 4 + 3 = 12, we are left with 14 people who have taken only E. Similarly for M and S too.

Attachment:

Ques3.jpg [ 15.92 KiB | Viewed 3037 times ]

Now add all the students in the venn diagram = 14 + 5 + 13 + 3+ 4 + 6 + 5 = 50
_________________

Karishma
Veritas Prep | GMAT Instructor
My Blog

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

Veritas Prep Reviews

Intern
Joined: 15 May 2014
Posts: 27
Followers: 0

Kudos [?]: 21 [0], given: 22

Re: When Professor Wang looked at the rosters for this term's [#permalink]

### Show Tags

30 Sep 2014, 02:44
it's easier and more efficient to use the formula rather than a venn diagram in the actual exam.

For this problem, the appropriate formula should be:
Total = Group 1 + Group 2 + Group 3 - (Sum of two group overlaps) + All three + Neither
Total = 26 + 28 + 18 - (9 + 7 + 10) + 4 + 0 = 50

FYI, if a question asks for "Exactly" two groups, the formula is slightly modified:
Total = Group 1 + Group 2 + Group 3 - (Sum of Exactly 2 group overlaps) - (2 x All Three) + Neither
SVP
Status: The Best Or Nothing
Joined: 27 Dec 2012
Posts: 1858
Location: India
Concentration: General Management, Technology
WE: Information Technology (Computer Software)
Followers: 47

Kudos [?]: 1937 [0], given: 193

Re: When Professor Wang looked at the rosters for this term's [#permalink]

### Show Tags

01 Oct 2014, 00:13
It takes more time to read the problem, otherwise the Venn diagram is quite straightforward

Total students = 26 + (5+6) + 13 = 50

_________________

Kindly press "+1 Kudos" to appreciate

GMAT Club Legend
Joined: 09 Sep 2013
Posts: 13544
Followers: 578

Kudos [?]: 163 [0], given: 0

Re: When Professor Wang looked at the rosters for this term's [#permalink]

### Show Tags

21 Oct 2016, 01:18
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: When Professor Wang looked at the rosters for this term's   [#permalink] 21 Oct 2016, 01:18
Similar topics Replies Last post
Similar
Topics:
A team captain must choose five players from a roster of 12 to start 2 28 Dec 2016, 00:46
10 At a certain committee meeting only associate professors and 6 23 Nov 2012, 18:57
1 A professor will assign seven projects to three students. If 8 01 Oct 2011, 00:25
26 At a certain university, 60% of the professors are women, an 18 14 Nov 2009, 07:33
29 4 professors and 6 students are being considered for 31 27 Oct 2009, 05:28
Display posts from previous: Sort by