It is currently 19 Nov 2017, 23:35

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

Events & Promotions in June
Open Detailed Calendar

M27-04

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

Hide Tags

Expert Post
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 42257

Kudos [?]: 132742 [0], given: 12360

M27-04 [#permalink]

Show Tags

New post 16 Sep 2014, 01:26
Expert's post
14
This post was
BOOKMARKED
00:00
A
B
C
D
E

Difficulty:

  95% (hard)

Question Stats:

36% (01:10) correct 64% (01:26) wrong based on 53 sessions

HideShow timer Statistics

If at least one astronaut does NOT listen to Bach at Solaris space station, then how many of 35 astronauts at Solaris space station listen to Bach?


(1) Of the astronauts who do NOT listen to Bach, 56% are male.

(2) Of the astronauts who listen to Bach, 70% are female.
[Reveal] Spoiler: OA

_________________

New to the Math Forum?
Please read this: Ultimate GMAT Quantitative Megathread | All You Need for Quant | PLEASE READ AND FOLLOW: 12 Rules for Posting!!!

Resources:
GMAT Math Book | Triangles | Polygons | Coordinate Geometry | Factorials | Circles | Number Theory | Remainders; 8. Overlapping Sets | PDF of Math Book; 10. Remainders | GMAT Prep Software Analysis | SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) | Tricky questions from previous years.

Collection of Questions:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
Extra-hard Quant Tests with Brilliant Analytics

Kudos [?]: 132742 [0], given: 12360

Expert Post
5 KUDOS received
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 42257

Kudos [?]: 132742 [5], given: 12360

Re M27-04 [#permalink]

Show Tags

New post 16 Sep 2014, 01:26
5
This post received
KUDOS
Expert's post
1
This post was
BOOKMARKED
Official Solution:


Tricky question.

(1) Of the astronauts who do NOT listen to Bach, 56% are male. If # of astronauts who do NOT listen to Bach is \(x\), then \(0.56x\) is # of males who do NOT listen to Bach. Notice that \(0.56x=\frac{14}{25}x\) must be an integer. Hence, \(x\) must be a multiple of 25: 25, 50, 75, ... But \(x\) (# of astronauts who do NOT listen to Bach) must also be less than (or equal to) 35. So \(x\) can only be 25, which makes # of astronauts who do listen to Bach equal to \(35-25=10\). Sufficient.

(2) Of the astronauts who listen to Bach, 70% are female. Now, if we apply the same logic here we get that, if # of astronauts who listen to Bach is \(y\), then \(0.7y\) is # of females who listen to Bach: \(0.7y=\frac{7}{10}y\) must be an integer. Hence, it must be a multiple of 10, but in this case it can take more than 1 value: 10, 20, 30. So, this statement is not sufficient.


Answer: A
_________________

New to the Math Forum?
Please read this: Ultimate GMAT Quantitative Megathread | All You Need for Quant | PLEASE READ AND FOLLOW: 12 Rules for Posting!!!

Resources:
GMAT Math Book | Triangles | Polygons | Coordinate Geometry | Factorials | Circles | Number Theory | Remainders; 8. Overlapping Sets | PDF of Math Book; 10. Remainders | GMAT Prep Software Analysis | SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) | Tricky questions from previous years.

Collection of Questions:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
Extra-hard Quant Tests with Brilliant Analytics

Kudos [?]: 132742 [5], given: 12360

1 KUDOS received
Intern
Intern
avatar
Joined: 19 Jun 2016
Posts: 15

Kudos [?]: 20 [1], given: 36

GMAT ToolKit User
Re: M27-04 [#permalink]

Show Tags

New post 11 Aug 2016, 21:51
1
This post received
KUDOS
Excellent Question.

Kudos [?]: 20 [1], given: 36

Intern
Intern
avatar
Joined: 29 Jan 2013
Posts: 42

Kudos [?]: 5 [0], given: 2

Location: United States
Concentration: Operations, Leadership
Schools: Booth PT '20 (M)
GMAT 1: 650 Q50 V26
WE: Manufacturing and Production (Manufacturing)
Reviews Badge
Re M27-04 [#permalink]

Show Tags

New post 17 Aug 2016, 04:33
I think this is a high-quality question and I agree with explanation. Very good question

Kudos [?]: 5 [0], given: 2

Intern
Intern
avatar
Joined: 12 Oct 2016
Posts: 7

Kudos [?]: 5 [0], given: 5

Re: M27-04 [#permalink]

Show Tags

New post 29 Oct 2016, 09:28
For this question, I believe it is helpful to draw a "grid", sort of like this:

Bach NotBach Total

Male

Female

Total >=1 35

And then fill in with the informations from statements 1 and 2. That's how I figured that the 0.56*x and 0.7*x had to be integers.

Kudos [?]: 5 [0], given: 5

Intern
Intern
User avatar
B
Joined: 07 May 2015
Posts: 23

Kudos [?]: 4 [0], given: 51

Re: M27-04 [#permalink]

Show Tags

New post 31 Oct 2016, 06:00
How to quickly convert the decimal to fraction such as these?
0.56X = [14][/25]X
Please help.

Kudos [?]: 4 [0], given: 51

Expert Post
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 42257

Kudos [?]: 132742 [0], given: 12360

Re: M27-04 [#permalink]

Show Tags

New post 31 Oct 2016, 06:06

Kudos [?]: 132742 [0], given: 12360

Intern
Intern
avatar
B
Joined: 07 Oct 2016
Posts: 13

Kudos [?]: 35 [0], given: 3

Re M27-04 [#permalink]

Show Tags

New post 01 Nov 2016, 16:18
I think this is a high-quality question and the explanation isn't clear enough, please elaborate. "If at least one astronaut does NOT listen to Bach"

1. What would have happened if the question stem did not have these words?? 2. what is the significance of these words?
3. How would it change the answer

Kudos [?]: 35 [0], given: 3

Intern
Intern
avatar
B
Joined: 23 Aug 2014
Posts: 5

Kudos [?]: 1 [0], given: 7

Reviews Badge CAT Tests
Re: M27-04 [#permalink]

Show Tags

New post 20 Aug 2017, 20:51
Bunuel wrote:
Official Solution:


Tricky question.

(1) Of the astronauts who do NOT listen to Bach, 56% are male. If # of astronauts who do NOT listen to Bach is \(x\), then \(0.56x\) is # of males who do NOT listen to Bach. Notice that \(0.56x=\frac{14}{25}x\) must be an integer. Hence, \(x\) must be a multiple of 25: 25, 50, 75, ... But \(x\) (# of astronauts who do NOT listen to Bach) must also be less than (or equal to) 35. So \(x\) can only be 25, which makes # of astronauts who do listen to Bach equal to \(35-25=10\). Sufficient.

(2) Of the astronauts who listen to Bach, 70% are female. Now, if we apply the same logic here we get that, if # of astronauts who listen to Bach is \(y\), then \(0.7y\) is # of females who listen to Bach: \(0.7y=\frac{7}{10}y\) must be an integer. Hence, it must be a multiple of 10, but in this case it can take more than 1 value: 10, 20, 30. So, this statement is not sufficient.


Answer: A


Hi Bunuel,

I have one doubt. Can you please help to clarify.

Its given in Option 1 that "Of the astronauts who do NOT listen to Bach, 56% are male" & from our calculation, its been found that the no is 25. Now we also need to consider the No of Females who do NOT listen to Bach. Without considering that , how are we arriving at the conclusion that :-

"# of astronauts who do listen to Bach equal to 35-25=10 " ?

Can you please clarify further.

Kudos [?]: 1 [0], given: 7

Expert Post
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 42257

Kudos [?]: 132742 [0], given: 12360

M27-04 [#permalink]

Show Tags

New post 21 Aug 2017, 03:37
ran787 wrote:
Bunuel wrote:
Official Solution:


Tricky question.

(1) Of the astronauts who do NOT listen to Bach, 56% are male. If # of astronauts who do NOT listen to Bach is \(x\), then \(0.56x\) is # of males who do NOT listen to Bach. Notice that \(0.56x=\frac{14}{25}x\) must be an integer. Hence, \(x\) must be a multiple of 25: 25, 50, 75, ... But \(x\) (# of astronauts who do NOT listen to Bach) must also be less than (or equal to) 35. So \(x\) can only be 25, which makes # of astronauts who do listen to Bach equal to \(35-25=10\). Sufficient.

(2) Of the astronauts who listen to Bach, 70% are female. Now, if we apply the same logic here we get that, if # of astronauts who listen to Bach is \(y\), then \(0.7y\) is # of females who listen to Bach: \(0.7y=\frac{7}{10}y\) must be an integer. Hence, it must be a multiple of 10, but in this case it can take more than 1 value: 10, 20, 30. So, this statement is not sufficient.


Answer: A


Hi Bunuel,

I have one doubt. Can you please help to clarify.

Its given in Option 1 that "Of the astronauts who do NOT listen to Bach, 56% are male" & from our calculation, its been found that the no is 25. Now we also need to consider the No of Females who do NOT listen to Bach. Without considering that , how are we arriving at the conclusion that :-

"# of astronauts who do listen to Bach equal to 35-25=10 " ?

Can you please clarify further.


x (25) in the solution denotes the number of astronauts who do not listen to Bach, x is NOT the number of male astronauts who listen to Bach.
_________________

New to the Math Forum?
Please read this: Ultimate GMAT Quantitative Megathread | All You Need for Quant | PLEASE READ AND FOLLOW: 12 Rules for Posting!!!

Resources:
GMAT Math Book | Triangles | Polygons | Coordinate Geometry | Factorials | Circles | Number Theory | Remainders; 8. Overlapping Sets | PDF of Math Book; 10. Remainders | GMAT Prep Software Analysis | SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) | Tricky questions from previous years.

Collection of Questions:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
Extra-hard Quant Tests with Brilliant Analytics

Kudos [?]: 132742 [0], given: 12360

Manager
Manager
User avatar
G
Joined: 01 Sep 2016
Posts: 208

Kudos [?]: 184 [0], given: 33

GMAT 1: 690 Q49 V35
GMAT ToolKit User Reviews Badge CAT Tests
Re: M27-04 [#permalink]

Show Tags

New post 17 Sep 2017, 10:10
Bunuel wrote:
Official Solution:


Tricky question.

(1) Of the astronauts who do NOT listen to Bach, 56% are male. If # of astronauts who do NOT listen to Bach is \(x\), then \(0.56x\) is # of males who do NOT listen to Bach. Notice that \(0.56x=\frac{14}{25}x\) must be an integer. Hence, \(x\) must be a multiple of 25: 25, 50, 75, ... But \(x\) (# of astronauts who do NOT listen to Bach) must also be less than (or equal to) 35. So \(x\) can only be 25, which makes # of astronauts who do listen to Bach equal to \(35-25=10\). Sufficient.

(2) Of the astronauts who listen to Bach, 70% are female. Now, if we apply the same logic here we get that, if # of astronauts who listen to Bach is \(y\), then \(0.7y\) is # of females who listen to Bach: \(0.7y=\frac{7}{10}y\) must be an integer. Hence, it must be a multiple of 10, but in this case it can take more than 1 value: 10, 20, 30. So, this statement is not sufficient.


Answer: A



Wonderfulllll! This is such an awesome question. Love the explanation as well. The important point to note here is that we are dealing with people, so we have to take care that we are dealing with integers. First sight at the option choices indicate that the answer is E. but once you drill deeper, you realize that answer is A. Excellent question.
_________________

we shall fight on the beaches,
we shall fight on the landing grounds,
we shall fight in the fields and in the streets,
we shall fight in the hills;
we shall never surrender!

Kudos [?]: 184 [0], given: 33

Re: M27-04   [#permalink] 17 Sep 2017, 10:10
Display posts from previous: Sort by

M27-04

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

Moderators: Bunuel, chetan2u



GMAT Club MBA Forum Home| About| Terms and Conditions| 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®.