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

It is currently 16 Feb 2019, 09:45

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 February
PrevNext
SuMoTuWeThFrSa
272829303112
3456789
10111213141516
17181920212223
242526272812
Open Detailed Calendar
  • Free GMAT Algebra Webinar

     February 17, 2019

     February 17, 2019

     07:00 AM PST

     09:00 AM PST

    Attend this Free Algebra Webinar and learn how to master Inequalities and Absolute Value problems on GMAT.
  • Free GMAT Strategy Webinar

     February 16, 2019

     February 16, 2019

     07:00 AM PST

     09:00 AM PST

    Aiming to score 760+? Attend this FREE session to learn how to Define your GMAT Strategy, Create your Study Plan and Master the Core Skills to excel on the GMAT.

M14-36

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

Hide Tags

 
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 52902
M14-36  [#permalink]

Show Tags

New post 15 Sep 2014, 23:54
1
3
00:00
A
B
C
D
E

Difficulty:

  75% (hard)

Question Stats:

43% (01:06) correct 57% (01:09) wrong based on 115 sessions

HideShow timer Statistics

Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 52902
Re M14-36  [#permalink]

Show Tags

New post 15 Sep 2014, 23:54
Official Solution:


Statement (1) by itself is sufficient. From S1 it follows that \(a + b - c\) is an integer. Thus, \(2(a + b - c)\) is an even integer.

Statement (2) by itself is insufficient. Consider \(a = b = c = 0\) (the answer is "no") and \(a = 1.25\), \(c = -1.25\), \(b = 0\) (the answer is "yes").


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

Intern
Intern
avatar
Joined: 05 Nov 2014
Posts: 1
Re M14-36  [#permalink]

Show Tags

New post 30 Jan 2015, 07:01
Wont 2(a+b-c) result into an even integer irrespective of the statements below? Thus, making either statement sufficient.
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 52902
Re: M14-36  [#permalink]

Show Tags

New post 30 Jan 2015, 07:37
apurvadubhashi wrote:
Wont 2(a+b-c) result into an even integer irrespective of the statements below? Thus, making either statement sufficient.


No. For example, if a+b-c=1/2, then 2(a+b-c)=1, or if a+b-c=1/3, then 2(a+b-c)=2/3, not an integer at all.
_________________

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

Manager
Manager
avatar
Joined: 14 Jul 2014
Posts: 92
M14-36  [#permalink]

Show Tags

New post 02 Feb 2015, 05:31
Fantastic question!

Just shows how questions that look so easy are actually so deceptive :)

Yeah .... even I marked D - Wrong Ans
Retired Moderator
User avatar
Joined: 06 Jul 2014
Posts: 1230
Location: Ukraine
Concentration: Entrepreneurship, Technology
GMAT 1: 660 Q48 V33
GMAT 2: 740 Q50 V40
GMAT ToolKit User Premium Member
Re: M14-36  [#permalink]

Show Tags

New post 12 Apr 2015, 10:29
Bunuel wrote:
Official Solution:


Statement (1) by itself is sufficient. From S1 it follows that \(a + b - c\) is an integer. Thus, \(2(a + b - c)\) is an even integer.

Statement (2) by itself is insufficient. Consider \(a = b = c = 0\) (the answer is "no") and \(a = 1.25\), \(c = -1.25\), \(b = 0\) (the answer is "yes").


Answer: A


I understand why answer is D but can't understand why in explanation used such example: \(a = 1.25\), \(c = -1.25\), \(b = 0\) is (the answer is "yes")
We have question "Is \(2(a+b−c)\) an odd?"
let's put this numbers in the question and we receive: \(2(1.25+0-1.25) = 0 = even\)

I think correct example will be \(a = \frac{1}{4}\) \(b = \frac{1}{4}\) and \(c =0\)
\(b = a - c\) :
\(\frac{1}{4} = \frac{1}{4} - 0\)

and \(2(a+b−c)\):
\(2(\frac{1}{4}+\frac{1}{4}-0) = 1 = odd\)

Am I miss something or this is misprint in explanation?
_________________

Simple way to always control time during the quant part.
How to solve main idea questions without full understanding of RC.
660 (Q48, V33) - unpleasant surprise
740 (Q50, V40, IR3) - anti-debrief ;)

Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 52902
Re: M14-36  [#permalink]

Show Tags

New post 14 Apr 2015, 04:40
1
Harley1980 wrote:
Bunuel wrote:
Official Solution:


Statement (1) by itself is sufficient. From S1 it follows that \(a + b - c\) is an integer. Thus, \(2(a + b - c)\) is an even integer.

Statement (2) by itself is insufficient. Consider \(a = b = c = 0\) (the answer is "no") and \(a = 1.25\), \(c = -1.25\), \(b = 0\) (the answer is "yes").


Answer: A


I understand why answer is D but can't understand why in explanation used such example: \(a = 1.25\), \(c = -1.25\), \(b = 0\) is (the answer is "yes")
We have question "Is \(2(a+b−c)\) an odd?"
let's put this numbers in the question and we receive: \(2(1.25+0-1.25) = 0 = even\)

I think correct example will be \(a = \frac{1}{4}\) \(b = \frac{1}{4}\) and \(c =0\)
\(b = a - c\) :
\(\frac{1}{4} = \frac{1}{4} - 0\)

and \(2(a+b−c)\):
\(2(\frac{1}{4}+\frac{1}{4}-0) = 1 = odd\)

Am I miss something or this is misprint in explanation?


If \(a = 1.25\), \(c = -1.25\), \(b = 0\), then \(2(a + b - c) = 2(1.25+0 -(-1.25)) = 2*2.5=5\), not 0.
_________________

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

Manager
Manager
avatar
G
Joined: 30 Dec 2016
Posts: 239
GMAT 1: 650 Q42 V37
GPA: 4
WE: Business Development (Other)
Premium Member Reviews Badge
Re: M14-36  [#permalink]

Show Tags

New post 02 Jan 2018, 02:52
1
Another way to solve statement 2.

Is 2(a+b−c) an odd integer?

(2) b=a+c


Put b=a+c in original equation.
2(a+a+c-c)--> 2*2a.
If a= 1/4 then 2*2*1/4 is odd. And if a= any odd or even integer 2*2a will be even. Insufficient.

Answer: A
_________________

Regards
SandySilva


____________
Please appreciate the efforts by pressing +1 KUDOS (:

Manager
Manager
avatar
B
Joined: 02 Jan 2016
Posts: 123
Reviews Badge CAT Tests
Re: M14-36  [#permalink]

Show Tags

New post 12 May 2018, 21:57
Hello,

The explanation given by Bunuel, is very short and need more background.

We all know that any number multiplied by 2 is an Even Number, so it might seem like the question stem has the answer in itself, but do note that the question says, Even Integer , so if any of the variable in the given expression is a fraction, then the answer is No and variable is an Integer than Yes.

Statement 1 :- This statement clarifies that the variable in the expression are Integers, so sufficient

Statement 2: The expression: b = a+c, means a= b-c, replacing this in the question stem: therefore 2(a+a), but we dont know whether "a" is an integer or not, so not sufficient.
Intern
Intern
avatar
Joined: 02 Oct 2018
Posts: 1
CAT Tests
Re: M14-36  [#permalink]

Show Tags

New post 03 Feb 2019, 11:03
Guys, what if consecutive integers in S1 are 1, 2 and 3? Then we have 2*(1+2-3)=0 and thus option A is insufficient?
Director
Director
avatar
G
Joined: 09 Mar 2018
Posts: 929
Location: India
Re: M14-36  [#permalink]

Show Tags

New post 03 Feb 2019, 11:14
Bunuel wrote:
Is \(2(a + b - c)\) an odd integer?


(1) \(a\), \(b\), and \(c\) are consecutive integers

(2) \(b = a + c\)


1) a , b and c are consecutive integers, This will give value as a No for all the test cases

1,2,3
3,2,1

2) b = a+c

2 (2a)

4a, now a can be 1/4 which will answer the question as a Yes

or a = 1, which will answer the question as a No

A
_________________

If you notice any discrepancy in my reasoning, please let me know. Lets improve together.

Quote which i can relate to.
Many of life's failures happen with people who do not realize how close they were to success when they gave up.

Director
Director
avatar
G
Joined: 09 Mar 2018
Posts: 929
Location: India
Re: M14-36  [#permalink]

Show Tags

New post 03 Feb 2019, 11:15
lenakuz wrote:
Guys, what if consecutive integers in S1 are 1, 2 and 3? Then we have 2*(1+2-3)=0 and thus option A is insufficient?


Hi lenakuz

It wont be insufficient, it will answer the question as a No

is 0 an odd integer, No it is an even integer.
_________________

If you notice any discrepancy in my reasoning, please let me know. Lets improve together.

Quote which i can relate to.
Many of life's failures happen with people who do not realize how close they were to success when they gave up.

GMAT Club Bot
Re: M14-36   [#permalink] 03 Feb 2019, 11:15
Display posts from previous: Sort by

M14-36

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

Moderators: chetan2u, Bunuel



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®.