Oct 20 07:00 AM PDT  09:00 AM PDT Get personalized insights on how to achieve your Target Quant Score. Oct 22 08:00 PM PDT  09:00 PM PDT On Demand for $79. For a score of 4951 (from current actual score of 40+) AllInOne Standard & 700+ Level Questions (150 questions) Oct 23 08:00 AM PDT  09:00 AM PDT Join an exclusive interview with the people behind the test. If you're taking the GMAT, this is a webinar you cannot afford to miss!
Author 
Message 
TAGS:

Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 58449

Among a group of 2,500 people, 35 percent invest in
[#permalink]
Show Tags
14 Jun 2012, 02:49
Question Stats:
81% (02:15) correct 19% (02:39) wrong based on 2518 sessions
HideShow timer Statistics
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 Diagnostic Test Question: 4 Page: 20 Difficulty: 650
Official Answer and Stats are available only to registered users. Register/ Login.
_________________




Math Expert
Joined: 02 Sep 2009
Posts: 58449

Re: Among a group of 2,500 people, 35 percent invest in
[#permalink]
Show Tags
14 Jun 2012, 02:49
SOLUTIONAmong 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 Given: \(0.35*2,500=875\) invest in municipal bonds; \(0.07*2,500=175\) invest in in both municipal bonds and oil stocks; Therefore \(875175=700\) invest in municipal bonds but NOT in in oil stocks. (Or directly: 35%7%=28% of 2,500, which is 700, invest in municipal bonds but NOT in in oil stocks). \(P=\frac{Favorable}{Total}=\frac{700}{2,500}=\frac{7}{25}\). Answer: B.
_________________




Current Student
Joined: 29 Mar 2012
Posts: 295
Location: India
GMAT 1: 640 Q50 V26 GMAT 2: 660 Q50 V28 GMAT 3: 730 Q50 V38

Re: Among a group of 2,500 people, 35 percent invest in
[#permalink]
Show Tags
Updated on: 09 Jul 2012, 01:04
Quote: 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
Hi, 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. As per the attached venn diagram, we have to find the number of people in shaded portion. =35%7%=28% Thus, probability = 0.28 = 7/25 (2,500 people, 18 percent invest in oil stocks is not required.) Answer is (B)
Attachments
m.jpg [ 9.55 KiB  Viewed 55357 times ]
Originally posted by cyberjadugar on 14 Jun 2012, 06:09.
Last edited by cyberjadugar on 09 Jul 2012, 01:04, edited 1 time in total.




Manager
Joined: 02 Jun 2011
Posts: 114

Re: Among a group of 2,500 people, 35 percent invest in
[#permalink]
Show Tags
14 Jun 2012, 06:50
People with Municipal Bond but not with Oil Stock = People with Municipal Bond and Oil stock – People with Municipal Bond but not Oil S = 35%of 2500 – 7% of 2500 = 700 Now, P ( one person investing in Municipal Bond but not in Oil Stock ) = 700 /2500 = 7/25
Answer B



Intern
Joined: 03 Jun 2012
Posts: 24
Location: United States
WE: Project Management (Computer Software)

Re: Among a group of 2,500 people, 35 percent invest in
[#permalink]
Show Tags
14 Jun 2012, 20:19
Percentage investing in Municipal bonds = 35% Percentage investing in both = 7% Percentage investing in ONLY Municipal bonds = (357)% = 28%
Therefore, Probability of selecting one who invests Only in Municipal bonds = 28% = 28/100 = 7/25. Answer (B) is correct.



Manager
Joined: 07 Sep 2011
Posts: 59
Location: United States
Concentration: Strategy, International Business
WE: General Management (Real Estate)

Re: Among a group of 2,500 people, 35 percent invest in
[#permalink]
Show Tags
16 Jun 2012, 03:52
Difficulty level 600+.
Probability of percentage invested in MB/ Total
35%7%=28% of 2500= 700
P= 700/2500= 7/25



Director
Joined: 22 Mar 2011
Posts: 588
WE: Science (Education)

Re: Among a group of 2,500 people, 35 percent invest in
[#permalink]
Show Tags
Updated on: 18 Jun 2012, 08:14
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=187, 28=357, 82=10018, 54=8228, 65=10035. 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
OG13Diagn4.jpg [ 36.89 KiB  Viewed 55074 times ]
_________________
PhD in Applied Mathematics Love GMAT Quant questions and running.
Originally posted by EvaJager on 18 Jun 2012, 07:07.
Last edited by EvaJager on 18 Jun 2012, 08:14, edited 1 time in total.



Veritas Prep GMAT Instructor
Joined: 16 Oct 2010
Posts: 9706
Location: Pune, India

Re: Confusing Quant Prob
[#permalink]
Show Tags
11 Jun 2015, 20:43
LouieV wrote: 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 ! 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: http://www.veritasprep.com/blog/2012/09 ... pingsets/
_________________
Karishma Veritas Prep GMAT Instructor
Learn more about how Veritas Prep can help you achieve a great GMAT score by checking out their GMAT Prep Options >



CEO
Status: GMATINSIGHT Tutor
Joined: 08 Jul 2010
Posts: 2978
Location: India
GMAT: INSIGHT
WE: Education (Education)

Confusing Quant Prob
[#permalink]
Show Tags
11 Jun 2015, 20:49
LouieV wrote: 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 ! 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 = 0.820.54 = 0.28 = 28/100 = 7/25 Answer: Option
Attachments
File comment: www.GMATinsight.com
113.jpg [ 73.99 KiB  Viewed 41890 times ]
_________________
Prosper!!!GMATinsightBhoopendra Singh and Dr.Sushma Jha email: info@GMATinsight.com I Call us : +919999687183 / 9891333772 Online OneonOne Skype based classes and Classroom Coaching in South and West Delhihttp://www.GMATinsight.com/testimonials.htmlACCESS FREE GMAT TESTS HERE:22 ONLINE FREE (FULL LENGTH) GMAT CAT (PRACTICE TESTS) LINK COLLECTION



Intern
Joined: 11 Jun 2015
Posts: 1

Confusing Quant Prob
[#permalink]
Show Tags
11 Jun 2015, 21:46
Thank you for explaining this in such simple terms Karishma. GMATinsight, the visual was definitely a big help in allowing me to see the arithmetic behind the words. I was stomped, but I'm sure my gears will get back to speed as I progress in my preparation. THANKS EVERYONE!



Senior Manager
Joined: 10 Mar 2013
Posts: 465
Location: Germany
Concentration: Finance, Entrepreneurship
GPA: 3.88
WE: Information Technology (Consulting)

Re: Among a group of 2,500 people, 35 percent invest in
[#permalink]
Show Tags
04 Sep 2015, 01:59
The fastest way is from Bunuel, but in this case I would stay with percents, as it is easier to calculate: 35%7%(overlap)=28% > 28%/100%=7/25
Attachments
PS D4.JPG [ 19.36 KiB  Viewed 38357 times ]
_________________
When you’re up, your friends know who you are. When you’re down, you know who your friends are.
Share some Kudos, if my posts help you. Thank you !
800Score ONLY QUANT CAT1 51, CAT2 50, CAT3 50 GMAT PREP 670 MGMAT CAT 630 KAPLAN CAT 660



Manager
Joined: 10 May 2014
Posts: 136

Re: Among a group of 2,500 people, 35 percent invest in
[#permalink]
Show Tags
04 Sep 2015, 08:16
The piece of information that states that "there are 2,500 people" is completely irrelevant, right? In other words you can yield the correct answer without that piece of data.
_________________
Consider giving me Kudos if I helped, but don´t take them away if I didn´t! What would you do if you weren´t afraid?



Manager
Joined: 01 Jun 2013
Posts: 102

Among a group of 2,500 people, 35 percent invest in
[#permalink]
Show Tags
07 Sep 2015, 11:53
No need to calculate number of people Both OS and Muni: 7%, therefore, Muni only: 28% and OS only:11% Muni Only / All = 28%/1 >> 7/25
_________________
Please kindly click on "+1 Kudos", if you think my post is useful



Manager
Joined: 17 Mar 2014
Posts: 122
Location: United States
Concentration: Entrepreneurship, Leadership
GPA: 3.97

Re: Among a group of 2,500 people, 35 percent invest in
[#permalink]
Show Tags
08 Dec 2015, 09:29
Bunuel wrote: 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 Diagnostic Test Question: 4 Page: 20 Difficulty: 650 For this Q  I was thinking why cant we assume that "35%" mentioned only include people that invest in municipal bonds. But Karishma from Veriats cleared the doubt. ONLY should have been mentioned  if that was the case. Below excerpts of her reply  "Yes, if they say, " 35% invest in municipal bonds only and 7% invest in both," then the two are mutually exclusive."
_________________
KUDOS!!!, I need them too



Intern
Joined: 01 Aug 2015
Posts: 1

Re: Among a group of 2,500 people, 35 percent invest in
[#permalink]
Show Tags
17 Jan 2016, 07:44
Question  why isn't it 0.35 * 0.82 (the number of people who don't invest in oil) ?
Thanks much.



CEO
Joined: 20 Mar 2014
Posts: 2597
Concentration: Finance, Strategy
GPA: 3.7
WE: Engineering (Aerospace and Defense)

Re: Among a group of 2,500 people, 35 percent invest in
[#permalink]
Show Tags
17 Jan 2016, 08:08
nellietyf wrote: Question  why isn't it 0.35 * 0.82 (the number of people who don't invest in oil) ?
Thanks much. Because those 82% people also include people who do not go for either the municipal bonds or the stocks. Refer to the attached figure. Text in red : calculated, text in black: calculated. Attachment:
20160117_100718.jpg [ 22.63 KiB  Viewed 22552 times ]
Thus the required probability =700/2500 = 7/25. B is thus the correct answer. Hope this helps.



Intern
Joined: 13 Oct 2011
Posts: 4

Among a group of 2,500 people, 35 percent invest in
[#permalink]
Show Tags
20 Sep 2016, 13:48
Why didn't we say: P( bonds only) & P(not oil), which is P(bonds only) & P(1 p(oil))?? Isn't it the translation of NOT oil? This is contradicting with solution of this OG PS question: 215 Xavier, Yvonne, and Zelda each try independently to solve a problem. If their individual probabilities for success are 1/4, 1/2 and 5/8, respectively, what is the probability that Xavier and Yvonne, but not Zelda, will solve the problem? The solution considered the p(not zelda)! I am confused.



Manager
Joined: 07 Jun 2017
Posts: 161
Location: India
Concentration: Technology, General Management
GPA: 3.6
WE: Information Technology (Computer Software)

Re: Among a group of 2,500 people, 35 percent invest in
[#permalink]
Show Tags
11 Dec 2017, 23:23
People with Municipal Bond and Oil stock – People with Municipal Bond but not Oil S = 35%of 2500 – 7% of 2500 = 700 700 /2500 = 7/25 Answer B
_________________
Regards, Naveen email: nkmungila@gmail.com Please press kudos if you like this post



VP
Joined: 09 Mar 2016
Posts: 1230

Re: Among a group of 2,500 people, 35 percent invest in
[#permalink]
Show Tags
25 Feb 2018, 04:45
Bunuel wrote: SOLUTION
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
Given: \(0.35*2,500=875\) invest in municipal bonds; \(0.07*2,500=175\) invest in in both municipal bonds and oil stocks;
Therefore \(875175=700\) invest in municipal bonds but NOT in in oil stocks. (Or directly: 35%7%=28% of 2,500, which is 700, invest in municipal bonds but NOT in in oil stocks).
\(P=\frac{Favorable}{Total}=\frac{700}{2,500}=\frac{7}{25}\).
Answer: B. Bunuel is there a shortcut to calculate percent when it comes to big numbers. Quote time consuming.... \(0.35*2,500=875\) invest in municipal bonds; \(0.07*2,500=175\) invest in in both municipal bonds and oil stocks;



Target Test Prep Representative
Status: Founder & CEO
Affiliations: Target Test Prep
Joined: 14 Oct 2015
Posts: 8109
Location: United States (CA)

Re: Among a group of 2,500 people, 35 percent invest in
[#permalink]
Show Tags
12 Apr 2018, 16:29
Bunuel wrote: 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
_________________
5star rated online GMAT quant self study course See why Target Test Prep is the top rated GMAT quant course on GMAT Club. Read Our Reviews If you find one of my posts helpful, please take a moment to click on the "Kudos" button.




Re: Among a group of 2,500 people, 35 percent invest in
[#permalink]
12 Apr 2018, 16:29



Go to page
1 2
Next
[ 22 posts ]



