Last visit was: 22 Apr 2026, 03:55 It is currently 22 Apr 2026, 03:55
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.
Close
Request Expert Reply
Confirm Cancel
505-555 (Easy)|   Overlapping Sets|   Percent and Interest Problems|   Probability|                        
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 22 Apr 2026
Posts: 109,740
Own Kudos:
Given Kudos: 105,817
Products:
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 109,740
Kudos: 810,535
 [221]
16
Kudos
Add Kudos
204
Bookmarks
Bookmark this Post
Most Helpful Reply
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 22 Apr 2026
Posts: 109,740
Own Kudos:
Given Kudos: 105,817
Products:
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 109,740
Kudos: 810,535
 [58]
32
Kudos
Add Kudos
26
Bookmarks
Bookmark this Post
User avatar
cyberjadugar
Joined: 29 Mar 2012
Last visit: 01 Apr 2026
Posts: 264
Own Kudos:
1,814
 [40]
Given Kudos: 23
Location: India
GMAT 1: 640 Q50 V26
GMAT 2: 660 Q50 V28
GMAT 3: 730 Q50 V38
GMAT 3: 730 Q50 V38
Posts: 264
Kudos: 1,814
 [40]
29
Kudos
Add Kudos
11
Bookmarks
Bookmark this Post
User avatar
EvaJager
Joined: 22 Mar 2011
Last visit: 31 Aug 2016
Posts: 513
Own Kudos:
2,370
 [26]
Given Kudos: 43
WE:Science (Education)
Posts: 513
Kudos: 2,370
 [26]
20
Kudos
Add Kudos
6
Bookmarks
Bookmark this Post
For this type of question, I sometimes use a 2X2 table approach. The table is just an organized summary of the Venn diagram.
Since in this case a probability is required, there is no need to calculate actual numbers. So, using percentages, we can fill out the table (see attached image). I started with 35, 18 and 7, then for example 11=18-7, 28=35-7, 82=100-18, 54=82-28, 65=100-35. There is more than one possible sequence. Necessarily, one must get the sum in the bottom row and that in the rightmost column exactly 100.
In fact, you don't need to fill out the whole table, once you have that Municipal and noOil represents 28%, you are done. I present the whole table just to illustrate the use of it.

So, those who invest in Municipal and noOil stocks represent 28%=28/100=7/25.

Correct asnwer is B.
Attachments

OG13-Diagn-4.jpg
OG13-Diagn-4.jpg [ 36.89 KiB | Viewed 126378 times ]

General Discussion
User avatar
gmatdog
Joined: 03 Jun 2012
Last visit: 06 Jul 2012
Posts: 22
Own Kudos:
165
 [5]
Given Kudos: 2
Location: United States
WE:Project Management (Computer Software)
Posts: 22
Kudos: 165
 [5]
3
Kudos
Add Kudos
2
Bookmarks
Bookmark this Post
Percentage investing in Municipal bonds = 35%
Percentage investing in both = 7%
Percentage investing in ONLY Municipal bonds = (35-7)% = 28%

Therefore, Probability of selecting one who invests Only in Municipal bonds = 28% = 28/100 = 7/25.
Answer (B) is correct.
User avatar
KarishmaB
Joined: 16 Oct 2010
Last visit: 21 Apr 2026
Posts: 16,439
Own Kudos:
79,381
 [9]
Given Kudos: 484
Location: Pune, India
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 16,439
Kudos: 79,381
 [9]
8
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post
LouieV
Hello everyone and thank you for this forum!!!

I admit it has been a few years since I've sat down to attack standardized test, but my GOODNESS :shock: ! Can someone please lend some wisdom on this problem from TOG 2016 pg 20 #4.

Among a group of 2500 people, 35% invest in municipal bonds, 18% invest in oil stocks, and 7% invest in both municipal bonds and oil stocks. If 1 person is randomly selected from the 2500 people, what is the probability that the person will be one who invests in municipal bonds but NOT in oil stocks?

A. 9/50
B. 7/25
C. 7/20
D. 21/50
E. 27/50

Thanks in advance!

So this question actually pertains to overlapping sets.

Say, there are 100 people instead (since we have percentages)
Number of people investing in MB = 35
Number of people investing in OS = 18
Number of people investing in both = 7

So how many people invest in MB but not OS? 35 invest in MB but 7 invest in both (so out of 35, 7 invest in OC too). We need to remove these 7 since we need the number of people who invest in MB only. We get 28.
So 28 out of 100 people invest in only MB. So out of 100, if we pick one person, the probability that he invests in MB only is 28/100 = 7/25

The probability remains same no matter how many people there are - 100 or 2500 or 500000 etc.

Answer (B)

Check out overlapping sets: https://www.gmatclub.com/forum/veritas-prep-resource-links-no-longer-available-399979.html#/2012/09 ... ping-sets/
User avatar
GMATinsight
User avatar
Major Poster
Joined: 08 Jul 2010
Last visit: 22 Apr 2026
Posts: 6,976
Own Kudos:
16,893
 [3]
Given Kudos: 128
Status:GMAT/GRE Tutor l Admission Consultant l On-Demand Course creator
Location: India
GMAT: QUANT+DI EXPERT
Schools: IIM (A) ISB '24
GMAT 1: 750 Q51 V41
WE:Education (Education)
Products:
Expert
Expert reply
Schools: IIM (A) ISB '24
GMAT 1: 750 Q51 V41
Posts: 6,976
Kudos: 16,893
 [3]
2
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post
LouieV
Hello everyone and thank you for this forum!!!

I admit it has been a few years since I've sat down to attack standardized test, but my GOODNESS :shock: ! Can someone please lend some wisdom on this problem from TOG 2016 pg 20 #4.

Among a group of 2500 people, 35% invest in municipal bonds, 18% invest in oil stocks, and 7% invest in both municipal bonds and oil stocks. If 1 person is randomly selected from the 2500 people, what is the probability that the person will be one who invests in municipal bonds but NOT in oil stocks?

A. 9/50
B. 7/25
C. 7/20
D. 21/50
E. 27/50

Thanks in advance!

Total People = 2500 people

35% invest in municipal bonds, i.e Probability of Investing in Mutual Bonds = 0.35
i.e. i.e Probability of NOT Investing in Mutual Bonds = 0.65

18% invest in oil stocks i.e Probability of Investing in Oil stock = 0.18
i.e Probability of NOT Investing in Oil stock = 0.82

7% invest in both municipal bonds and oil stocks = 0.07

i.e. we can conclude that Probability of NOT investing in any one of them = 1-(0.35+0.18+0.07) = 0.54

Probability of Investing in Mulual Bond but NOT in Oil Stock = 0.82-0.54 = 0.28 = 28/100 = 7/25

Answer: Option
Attachments

File comment: www.GMATinsight.com
113.jpg
113.jpg [ 73.99 KiB | Viewed 110431 times ]

User avatar
ScottTargetTestPrep
User avatar
Target Test Prep Representative
Joined: 14 Oct 2015
Last visit: 21 Apr 2026
Posts: 22,276
Own Kudos:
26,528
 [2]
Given Kudos: 302
Status:Founder & CEO
Affiliations: Target Test Prep
Location: United States (CA)
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 22,276
Kudos: 26,528
 [2]
1
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post
Bunuel
Among a group of 2,500 people, 35 percent invest in municipal bonds, 18 percent invest in oil stocks, and 7 percent invest in both municipal bonds and oil stocks. If 1 person is to be randomly selected from the 2,500 people, what is the probability that the person selected will be one who invests in municipal bonds but NOT in oil stocks?

(A) 9/50
(B) 7/25
(C) 7/20
(D) 21/50
(E) 27/50

The number of people who invest in ONLY municipal bonds is:

2,500 x 0.35 - 2,500 x 0.07

2,500(0.35 - 0.07) = 2,500(0.28) = 700

So, the probability that the person selected will be one who invests in municipal bonds and NOT in oil stocks is 700/2500 = 7/25.

Answer: B
User avatar
Basshead
Joined: 09 Jan 2020
Last visit: 07 Feb 2024
Posts: 907
Own Kudos:
323
 [2]
Given Kudos: 431
Location: United States
Posts: 907
Kudos: 323
 [2]
2
Kudos
Add Kudos
Bookmarks
Bookmark this Post
The key here is not to spend precious time converting the percentages. If we let the total = 100, we can determine that the percentage of people that invest in muni bonds & doesn't invest in oil stocks = 28.

28/100 = 7/25

This question should take less than a minute we simply keep the percentages.
Attachments

2500percent.PNG
2500percent.PNG [ 10.19 KiB | Viewed 44712 times ]

User avatar
DanTheGMATMan
Joined: 02 Oct 2015
Last visit: 18 Apr 2026
Posts: 380
Own Kudos:
Given Kudos: 9
Expert
Expert reply
Posts: 380
Kudos: 267
Kudos
Add Kudos
Bookmarks
Bookmark this Post
­Overlapping sets phrased as a probability:

­
User avatar
totaltestprepNick
Joined: 25 Aug 2014
Last visit: 21 Apr 2026
Posts: 469
Own Kudos:
Given Kudos: 2
GMAT 1: 750 Q49 V42
GMAT 1: 750 Q49 V42
Posts: 469
Kudos: 4
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Bunuel
Among a group of 2,500 people, 35 percent invest in municipal bonds, 18 percent invest in oil stocks, and 7 percent invest in both municipal bonds and oil stocks. If 1 person is to be randomly selected from the 2,500 people, what is the probability that the person selected will be one who invests in municipal bonds but NOT in oil stocks?

(A) 9/50
(B) 7/25
(C) 7/20
(D) 21/50
(E) 27/50





Nick Slavkovich, GMAT/GRE tutor with 20+ years of experience

[email protected]
User avatar
SKS27
Joined: 12 Dec 2025
Last visit: 07 Apr 2026
Posts: 1
Given Kudos: 64
Posts: 1
Kudos: 0
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Hi EvaJager,

Could you explain when it is preferred to use the Venn diagram and the 2x2 matrix to solve overlapping sets questions?

Many thanks!
EvaJager
For this type of question, I sometimes use a 2X2 table approach. The table is just an organized summary of the Venn diagram.
Since in this case a probability is required, there is no need to calculate actual numbers. So, using percentages, we can fill out the table (see attached image). I started with 35, 18 and 7, then for example 11=18-7, 28=35-7, 82=100-18, 54=82-28, 65=100-35. There is more than one possible sequence. Necessarily, one must get the sum in the bottom row and that in the rightmost column exactly 100.
In fact, you don't need to fill out the whole table, once you have that Municipal and noOil represents 28%, you are done. I present the whole table just to illustrate the use of it.

So, those who invest in Municipal and noOil stocks represent 28%=28/100=7/25.

Correct asnwer is B.
User avatar
dostwal
Joined: 01 Jun 2024
Last visit: 19 Apr 2026
Posts: 5
Own Kudos:
Given Kudos: 22
Posts: 5
Kudos: 3
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Visualising this problem as overlapping set or 2 set venn diagram can make it solve faster - we're asked on the probability that the person selected will be one who invests in municipal bonds but NOT in oil stocks which will be = [28]*2500[/100] divided by total number that is 2500. Simplifying this gives 7/25


Attachment:
GMAT-Club-Forum-mitjbo5f.png
GMAT-Club-Forum-mitjbo5f.png [ 121.5 KiB | Viewed 665 times ]
Moderators:
Math Expert
109740 posts
Tuck School Moderator
853 posts