GMAT Question of the Day - Daily to your Mailbox; hard ones only

It is currently 17 Dec 2018, 06:58

R1 Decisions:

Michigan Ross Chat (US calls are expected today)  |  UCLA Anderson Chat  (Calls expected to start at 7am PST; Applicants from Asia will hear first)


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
Events & Promotions in December
PrevNext
SuMoTuWeThFrSa
2526272829301
2345678
9101112131415
16171819202122
23242526272829
303112345
Open Detailed Calendar
  • 10 Keys to nail DS and CR questions

     December 17, 2018

     December 17, 2018

     06:00 PM PST

     07:00 PM PST

    Join our live webinar and learn how to approach Data Sufficiency and Critical Reasoning problems, how to identify the best way to solve each question and what most people do wrong.
  • R1 Admission Decisions: Estimated Decision Timelines and Chat Links for Major BSchools

     December 17, 2018

     December 17, 2018

     10:00 PM PST

     11:00 PM PST

    From Dec 5th onward, American programs will start releasing R1 decisions. Chat Rooms: We have also assigned chat rooms for every school so that applicants can stay in touch and exchange information/update during decision period.

60% of all students in a class commute by public transportation. If 30

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

e-GMAT Representative
User avatar
D
Joined: 04 Jan 2015
Posts: 2324
60% of all students in a class commute by public transportation. If 30  [#permalink]

Show Tags

New post Updated on: 07 Aug 2018, 00:13
3
16
00:00
A
B
C
D
E

Difficulty:

  65% (hard)

Question Stats:

58% (01:24) correct 42% (01:21) wrong based on 466 sessions

HideShow timer Statistics

Question 1 of The e-GMAT Sets Triad

60% of all students in a class commute by public transportation. If 30% of the students aspire to be scientists, which of the following can be the percentage of students who do not commute by public transportation and do not aspire to be scientists?
I. 5%
II. 30%
III. 60%

(A) I only
(B) II only
(C) III only
(D) I and II only
(E) I, II and III

Next Question

To read all our articles:Must Read articles to reach Q51

Image

_________________








Register for free sessions
Number Properties | Algebra |Quant Workshop

Success Stories
Guillermo's Success Story | Carrie's Success Story

Ace GMAT quant
Articles and Question to reach Q51 | Question of the week

Must Read Articles
Number Properties – Even Odd | LCM GCD | Statistics-1 | Statistics-2 | Remainders-1 | Remainders-2
Word Problems – Percentage 1 | Percentage 2 | Time and Work 1 | Time and Work 2 | Time, Speed and Distance 1 | Time, Speed and Distance 2
Advanced Topics- Permutation and Combination 1 | Permutation and Combination 2 | Permutation and Combination 3 | Probability
Geometry- Triangles 1 | Triangles 2 | Triangles 3 | Common Mistakes in Geometry
Algebra- Wavy line | Inequalities

Practice Questions
Number Properties 1 | Number Properties 2 | Algebra 1 | Geometry | Prime Numbers | Absolute value equations | Sets



| '4 out of Top 5' Instructors on gmatclub | 70 point improvement guarantee | www.e-gmat.com


Originally posted by EgmatQuantExpert on 13 May 2015, 06:31.
Last edited by EgmatQuantExpert on 07 Aug 2018, 00:13, edited 3 times in total.
e-GMAT Representative
User avatar
D
Joined: 04 Jan 2015
Posts: 2324
Re: 60% of all students in a class commute by public transportation. If 30  [#permalink]

Show Tags

New post Updated on: 14 May 2015, 22:11
2
2
The correct answer is Option B

The given information can be tabulated as below:

Image

To answer this question, we need to know the percentage range of X.

The maximum value of X is 40% (because for X > 40%, z becomes negative, and a negative value is not allowed for z since z denotes the number of a category of students)

Let’s now find the minimum value of X.

We can write:
Y + X = 70%
So, X = 70% - Y
The maximum value of Y is 60%
This means, the minimum possible value of X is 10%

Thus, X can have values between 10% - 40% of all students, inclusive.
_________________








Register for free sessions
Number Properties | Algebra |Quant Workshop

Success Stories
Guillermo's Success Story | Carrie's Success Story

Ace GMAT quant
Articles and Question to reach Q51 | Question of the week

Must Read Articles
Number Properties – Even Odd | LCM GCD | Statistics-1 | Statistics-2 | Remainders-1 | Remainders-2
Word Problems – Percentage 1 | Percentage 2 | Time and Work 1 | Time and Work 2 | Time, Speed and Distance 1 | Time, Speed and Distance 2
Advanced Topics- Permutation and Combination 1 | Permutation and Combination 2 | Permutation and Combination 3 | Probability
Geometry- Triangles 1 | Triangles 2 | Triangles 3 | Common Mistakes in Geometry
Algebra- Wavy line | Inequalities

Practice Questions
Number Properties 1 | Number Properties 2 | Algebra 1 | Geometry | Prime Numbers | Absolute value equations | Sets



| '4 out of Top 5' Instructors on gmatclub | 70 point improvement guarantee | www.e-gmat.com


Originally posted by EgmatQuantExpert on 13 May 2015, 07:04.
Last edited by EgmatQuantExpert on 14 May 2015, 22:11, edited 1 time in total.
Intern
Intern
avatar
Joined: 13 May 2015
Posts: 3
Re: 60% of all students in a class commute by public transportation. If 30  [#permalink]

Show Tags

New post 13 May 2015, 18:20
1
60% of the students commute by public transportation, so 40% don't. So the students don't commute by public transportation can't be 60%. Eliminate the third option.
If all students who don't commute by public transportation want to be scientists, then 10% don't commute by public transportation or want to be scientists. So at least 10% qualify. Eliminate the first option.
Manager
Manager
avatar
B
Joined: 12 Nov 2014
Posts: 63
Re: 60% of all students in a class commute by public transportation. If 30  [#permalink]

Show Tags

New post 13 May 2015, 18:24
4
Lets say there are 10 students in the class. (A B C D E F G H I J)
60% of these students travel by Public Transportation. i.e. 6 students.
30% of students aspire to be scientists i.e. 3 students.

Extreme Case I (No overlap)
A B C D E F travel by Public Transportation. G H I aspire to be scientists. Remaining 1 out of 10 i.e. 10% .
The percentage of students who do not travel by Public Transportation and who do not aspire to be scientists will be not less than 10%.

Extreme Case II (Complete overlap)
The three students who aspire to be scientists fall in the list of students who travel by Public Transportation
i.e. lets say A B C D E F travel by Public Transportation and A B C aspire to be scientists. So remaining will be 4 out of 10. i.e. 40 %
The percentage of students who do not travel by Public Transportation and who do not aspire to be scientists will be not be greater than 40%.

So the % of students who do not travel by Public Transportation and who do not aspire to be scientists will be between 10% -40 %
And there is only one answer in the choices. 30%

Answer B
Ambarish
_________________

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Kindly press Kudos if the explanation is clear.
Thank you
Ambarish

Current Student
User avatar
G
Joined: 28 Nov 2014
Posts: 857
Concentration: Strategy
Schools: Fisher '19 (M)
GPA: 3.71
Reviews Badge
Re: 60% of all students in a class commute by public transportation. If 30  [#permalink]

Show Tags

New post 14 May 2015, 10:29
2
60% of all students in a class commute by public transportation. If 30% of the students aspire to be scientists, which of the following can be the percentage of students who do not commute by public transportation and do not aspire to be scientists?
I. 5%
II. 30%
III. 60%

(A) I only
(B) II only
(C) III only
(D) I and II only
(E) I, II and III

________________________________________________

This question can easily be done with the help of a double matrix method, taking the total number of students as 60 (LCM of 30 and 60)

Try to substitute different possible values, 5% of 60, 30% of 60 and 60% of 60 and we can see that only II satisfies the double matrix condition.

Therefore, answer to this should be II only.
Retired Moderator
User avatar
S
Joined: 18 Sep 2014
Posts: 1116
Location: India
GMAT ToolKit User Premium Member Reviews Badge
Re: 60% of all students in a class commute by public transportation. If 30  [#permalink]

Show Tags

New post 14 May 2015, 11:18
4
Attachment:
soln.png
soln.png [ 11.8 KiB | Viewed 4828 times ]

Let x represent students who do not commute by public transportation and do not aspire to be scientists.
And assume total no of students is 100.
40-x<30
This implies x>10 i.e., answer is more than 10%.
As per the table values x should be less than 40
Therefore only Statement 2 can give possible value.
Option B is correct.
e-GMAT Representative
User avatar
D
Joined: 04 Jan 2015
Posts: 2324
Re: 60% of all students in a class commute by public transportation. If 30  [#permalink]

Show Tags

New post 14 May 2015, 22:21
kql5112, askhere, anewbeginning, Mechmeera: You all answered this question right! Great job done with the analysis! :)

Mechmeera: Just a slight correction in the solution posted by you:

You wrote 40 - x < 30

It should actually be 40 - x =< (less than or equal to) 30%

Do you see why the 'equal to' case is also possible?

Similarly, the correct upper limit for x will be: x > = 40%

Clarity about this nuance would be crucial to getting the question right, if the values given in options I, II and III were, say:
I. 5%
II. 10%
III. 30%

Hope this was useful! :)

Best Regards

Japinder
_________________








Register for free sessions
Number Properties | Algebra |Quant Workshop

Success Stories
Guillermo's Success Story | Carrie's Success Story

Ace GMAT quant
Articles and Question to reach Q51 | Question of the week

Must Read Articles
Number Properties – Even Odd | LCM GCD | Statistics-1 | Statistics-2 | Remainders-1 | Remainders-2
Word Problems – Percentage 1 | Percentage 2 | Time and Work 1 | Time and Work 2 | Time, Speed and Distance 1 | Time, Speed and Distance 2
Advanced Topics- Permutation and Combination 1 | Permutation and Combination 2 | Permutation and Combination 3 | Probability
Geometry- Triangles 1 | Triangles 2 | Triangles 3 | Common Mistakes in Geometry
Algebra- Wavy line | Inequalities

Practice Questions
Number Properties 1 | Number Properties 2 | Algebra 1 | Geometry | Prime Numbers | Absolute value equations | Sets



| '4 out of Top 5' Instructors on gmatclub | 70 point improvement guarantee | www.e-gmat.com

Current Student
User avatar
G
Joined: 28 Nov 2014
Posts: 857
Concentration: Strategy
Schools: Fisher '19 (M)
GPA: 3.71
Reviews Badge
Re: 60% of all students in a class commute by public transportation. If 30  [#permalink]

Show Tags

New post 14 May 2015, 22:34
EgmatQuantExpert wrote:
kql5112, askhere, anewbeginning, Mechmeera: You all answered this question right! Great job done with the analysis! :)

Mechmeera: Just a slight correction in the solution posted by you:

You wrote 40 - x < 30

It should actually be 40 - x =< (less than or equal to) 30%

Do you see why the 'equal to' case is also possible?

Similarly, the correct upper limit for x will be: x > = 40%

Clarity about this nuance would be crucial to getting the question right, if the values given in options I, II and III were, say:
I. 5%
II. 10%
III. 30%

Hope this was useful! :)

Best Regards

Japinder


Thank You EgmatQuantExpert for the question(s)
Retired Moderator
User avatar
S
Joined: 18 Sep 2014
Posts: 1116
Location: India
GMAT ToolKit User Premium Member Reviews Badge
Re: 60% of all students in a class commute by public transportation. If 30  [#permalink]

Show Tags

New post 14 May 2015, 23:16
EgmatQuantExpert wrote:
kql5112, askhere, anewbeginning, Mechmeera: You all answered this question right! Great job done with the analysis! :)

Mechmeera: Just a slight correction in the solution posted by you:

You wrote 40 - x < 30

It should actually be 40 - x =< (less than or equal to) 30%

Do you see why the 'equal to' case is also possible?

Similarly, the correct upper limit for x will be: x > = 40%

Clarity about this nuance would be crucial to getting the question right, if the values given in options I, II and III were, say:
I. 5%
II. 10%
III. 30%

Hope this was useful! :)

Best Regards

Japinder


Yes you are right.
Thank You EgmatQuantExpert for mentioning the point.
Intern
Intern
avatar
Joined: 01 Feb 2014
Posts: 1
Re: 60% of all students in a class commute by public transportation. If 30  [#permalink]

Show Tags

New post 15 May 2015, 14:43
1
This question can be solved easily by using Set Grid
Scientist Non Scientist Total
Public 60
Non Public X 40
Total 30 70 100

Now, lets check all possible value of X. This cannot be greater than 40, so 60% is gone right away.
Lets check for x=5%. If X=5%, the Non Public scientist would be 35%, which violates the 30% total sum rule. So, this way we can rule out 5%.

Lets check for x=30%. This fits well in our grid and is the only option. Hence answer choice (B)
Manager
Manager
avatar
B
Joined: 19 Aug 2016
Posts: 84
CAT Tests
Re: 60% of all students in a class commute by public transportation. If 30  [#permalink]

Show Tags

New post 20 Oct 2017, 23:30
Nevernevergiveup wrote:
Attachment:
soln.png

Let x represent students who do not commute by public transportation and do not aspire to be scientists.
And assume total no of students is 100.
40-x<30
This implies x>10 i.e., answer is more than 10%.
As per the table values x should be less than 40
Therefore only Statement 2 can give possible value.
Option B is correct.


Very nice explanation

Thanks
Non-Human User
User avatar
Joined: 09 Sep 2013
Posts: 9197
Premium Member
Re: 60% of all students in a class commute by public transportation. If 30  [#permalink]

Show Tags

New post 02 Nov 2018, 10:39
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

GMAT Club Bot
Re: 60% of all students in a class commute by public transportation. If 30 &nbs [#permalink] 02 Nov 2018, 10:39
Display posts from previous: Sort by

60% of all students in a class commute by public transportation. If 30

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  


Copyright

GMAT Club MBA Forum Home| About| Terms and Conditions and Privacy Policy| GMAT Club Rules| Contact| Sitemap

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne

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®.