Author 
Message 
TAGS:

Hide Tags

Intern
Joined: 27 Aug 2012
Posts: 17

Of the 500 business people surveyed, 78 percent said that [#permalink]
Show Tags
01 Dec 2012, 01:11
2
This post received KUDOS
4
This post was BOOKMARKED
Question Stats:
87% (01:12) correct 13% (01:24) wrong based on 245 sessions
HideShow timer Statistics
Of the 500 business people surveyed, 78 percent said that they use their laptop computers at home, 65 percent said that they use them in hotels, and 52 percent said that they use them both at home and in hotels. How many of the business people surveyed said that they do not use their laptop computers either at home or in hotels? A. 45 B. 55 C. 65 D. 95 E. 130 Can somebody give the formula for this overlapping set problem? P(AUB) = P(A)+P(B)P(A intersection B) I tried to use the domain matrix learnt from MGMAT. But somewhere I am going wrong, can someone help?
Official Answer and Stats are available only to registered users. Register/ Login.
Attachments
DSC_0112.jpg [ 3.01 MiB  Viewed 6256 times ]
Last edited by Bunuel on 22 Oct 2013, 23:13, edited 1 time in total.
Added the OA.



VP
Joined: 02 Jul 2012
Posts: 1212
Location: India
Concentration: Strategy
GPA: 3.8
WE: Engineering (Energy and Utilities)

Re: Overlapping sets [#permalink]
Show Tags
01 Dec 2012, 05:05
3
This post received KUDOS
SreeViji wrote: Of the 500 business people surveyed, 78 percent said that they use their laptop computers at home, 65 percent said that they use them in hotels, and 52 percent said that they use them both at home and in hotels. How many of the business people surveyed said that they do not use their laptop computers either at home or in hotels? A. 45 B. 55 C. 65 D. 95 E. 130 Can somebody give the formula for this overlapping set problem? P(AUB) = P(A)+P(B)P(A intersection B) I tried to use the domain matrix learnt from MGMAT. But somewhere I am going wrong, can someone help? I guess you made a mathematical error. Personally, I prefer creating the matrix in percentages when the question is given in percentages. And finally multiply what I want with the total. However for illustration the matrix should be
Attachments
Untitled.png [ 9.56 KiB  Viewed 6156 times ]
_________________
Did you find this post helpful?... Please let me know through the Kudos button.
Thanks To The Almighty  My GMAT Debrief
GMAT Reading Comprehension: 7 Most Common Passage Types



Intern
Joined: 27 Nov 2012
Posts: 37

Re: Overlapping sets [#permalink]
Show Tags
02 Dec 2012, 12:22
No reason to use formulas or weird pictures for this problem. Just think about what each set is.
I took the totals: 390 people use their laptop at home [1] 325 people use their laptop in hotels [2] 260 people use their laptop both in hotels and at home [3]
Clearly if someone uses their laptop both in hotels and at home, they belong in both the previous two sets (1,2). By subtracting set 3 from the first two, we can determine the number of people that lie in set 1 or set 2 but not in set 3.
Gives us: 130 only use their laptop at home 65 only use their laptop in hotels 260 use their laptop in both
add them up, subtract from the total and you get 45.



SVP
Status: The Best Or Nothing
Joined: 27 Dec 2012
Posts: 1839
Location: India
Concentration: General Management, Technology
WE: Information Technology (Computer Software)

Re: Of the 500 business people surveyed, 78 percent said that [#permalink]
Show Tags
22 Oct 2013, 21:36
Refer Venn diagram below:
Attachments
t.JPG [ 18.74 KiB  Viewed 5566 times ]
_________________
Kindly press "+1 Kudos" to appreciate



Intern
Joined: 14 Feb 2013
Posts: 3
GPA: 3.12

Re: Of the 500 business people surveyed, 78 percent said that [#permalink]
Show Tags
23 Oct 2013, 14:40
8
This post received KUDOS
1
This post was BOOKMARKED
I kept everything in percentage form since that is how the information was presented. I did not want to introduce calculations that could lead to an error.
I used the group formula:
Total = Group 1 + Group 2  Both + Neither.
Using the formula above and the information we are given:
100% = 78% + 65%  52% + Neither
100% = 91% + Neither or
Neither = 100%  91% = 9%
The total here is 500 so we can multiply 9% with 500 to get the amount of business people who do no use their laptops at home or in hotels.
(9/100) * 500 = 45
All of the methods mentioned above work, but I hope someone finds this helpful too. We can never have too many ways to approach a problem.



NonHuman User
Joined: 09 Sep 2013
Posts: 13815

Re: Of the 500 business people surveyed, 78 percent said that [#permalink]
Show Tags
08 Dec 2014, 12:33
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.
_________________
GMAT Books  GMAT Club Tests  Best Prices on GMAT Courses  GMAT Mobile App  Math Resources  Verbal Resources



Manager
Joined: 05 Jul 2015
Posts: 107
Concentration: Real Estate, International Business
GPA: 3.3

Re: Of the 500 business people surveyed, 78 percent said that [#permalink]
Show Tags
21 Nov 2015, 20:26
I used a chart like other people but left everything in percents and then calculated 9% of 500 = 45. I've found that the GMAT rewards you for procrastinating on doing calculations.



NonHuman User
Joined: 09 Sep 2013
Posts: 13815

Re: Of the 500 business people surveyed, 78 percent said that [#permalink]
Show Tags
28 Mar 2017, 00:24
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.
_________________
GMAT Books  GMAT Club Tests  Best Prices on GMAT Courses  GMAT Mobile App  Math Resources  Verbal Resources



Intern
Joined: 03 Dec 2016
Posts: 16
Location: United States
Concentration: Strategy, Finance
GPA: 3.97
WE: Business Development (Consulting)

Re: Of the 500 business people surveyed, 78 percent said that [#permalink]
Show Tags
04 Aug 2017, 12:45
Instead of using 500, just use 100 and then multiply the final answer by 5.
T=G1+G2Both+Neither 100=78+6552+X x=9 5*9=45
Takes 30 seconds.




Re: Of the 500 business people surveyed, 78 percent said that
[#permalink]
04 Aug 2017, 12:45






