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

It is currently 14 Nov 2018, 16:02

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 November
PrevNext
SuMoTuWeThFrSa
28293031123
45678910
11121314151617
18192021222324
2526272829301
Open Detailed Calendar
  • $450 Tuition Credit & Official CAT Packs FREE

     November 15, 2018

     November 15, 2018

     10:00 PM MST

     11:00 PM MST

    EMPOWERgmat is giving away the complete Official GMAT Exam Pack collection worth $100 with the 3 Month Pack ($299)
  • Free GMAT Strategy Webinar

     November 17, 2018

     November 17, 2018

     07:00 AM PST

     09:00 AM PST

    Nov. 17, 7 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.

M26-34

  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: 50585
M26-34  [#permalink]

Show Tags

New post 16 Sep 2014, 00:26
00:00
A
B
C
D
E

Difficulty:

  55% (hard)

Question Stats:

58% (00:56) correct 42% (00:57) wrong based on 216 sessions

HideShow timer Statistics

Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 50585
Re M26-34  [#permalink]

Show Tags

New post 16 Sep 2014, 00:26
Official Solution:


Must know for the GMAT: if \(x\) is a positive integer then \(\sqrt{x}\) is either a positive integer or an irrational number. (It cannot be some reduced fraction e.g. \(\frac{7}{3}\) or \(\frac{1}{2}\)).

Also, note that the question basically asks whether \(x\) is a perfect square.

(1) \(\sqrt{7*x}\) is an integer. This statement tells that \(x\) cannot be a perfect square, because if it is, for example if \(x=n^2\) for some positive integer \(n\), then \(\sqrt{7x}=\sqrt{7n^2}=n\sqrt{7} \ne integer\). Sufficient.

(2) \(\sqrt{9*x}\) is not an integer. Simplify: \(\sqrt{9*x}=3*\sqrt{x} \ne integer\), which means that \(\sqrt{x} \ne integer\). Sufficient.


Answer: D
_________________

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: 23 Apr 2016
Posts: 22
Location: Finland
Concentration: General Management, International Business
GPA: 3.65
Premium Member
Re: M26-34  [#permalink]

Show Tags

New post 07 Nov 2016, 09:32
Statement 1: x is squareroot of an odd power of 7, so not an integer. Sufficient.
Statement 2: x is not a perfect square, hence its square root will not be an integer. Sufficient.
Intern
Intern
avatar
B
Joined: 03 Dec 2014
Posts: 5
Re: M26-34  [#permalink]

Show Tags

New post 03 Sep 2018, 06:20
Statement 1: x needs to have odd number of 7 for \sqrt{7x} to be an integer. Hence \sqrt{x} cannot be an integer. Sufficient
Statement 2: Simplify to 3*\sqrt{x}. For this to be a non-integer, \sqrt{x} cannot be an integer. Sufficient
Intern
Intern
avatar
B
Joined: 17 Jun 2018
Posts: 11
Location: India
Schools: IMD '20
GPA: 2.84
WE: Engineering (Consulting)
Re: M26-34  [#permalink]

Show Tags

New post 08 Sep 2018, 21:47
Bunuel chetan2u
I am new to this community.I an unable to find options for answering these questions.Can you guide me.
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 50585
Re: M26-34  [#permalink]

Show Tags

New post 09 Sep 2018, 00:53
1
arpitkansal wrote:
Bunuel chetan2u
I am new to this community.I an unable to find options for answering these questions.Can you guide me.


This is a data sufficiency question. Options for DS questions are always the same.

The data sufficiency problem consists of a question and two statements, labeled (1) and (2), in which certain data are given. You have to decide whether the data given in the statements are sufficient for answering the question. Using the data given in the statements, plus your knowledge of mathematics and everyday facts (such as the number of days in July or the meaning of the word counterclockwise), you must indicate whether—

A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient to answer the question asked.
B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient to answer the question asked.
C. BOTH statements (1) and (2) TOGETHER are sufficient to answer the question asked, but NEITHER statement ALONE is sufficient to answer the question asked.
D. EACH statement ALONE is sufficient to answer the question asked.
E. Statements (1) and (2) TOGETHER are NOT sufficient to answer the question asked, and additional data specific to the problem are needed.

I suggest you to go through the following posts:
ALL YOU NEED FOR QUANT.
Ultimate GMAT Quantitative Megathread

Hope this helps.
_________________

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
B
Joined: 17 Jun 2018
Posts: 11
Location: India
Schools: IMD '20
GPA: 2.84
WE: Engineering (Consulting)
Re: M26-34  [#permalink]

Show Tags

New post 09 Sep 2018, 01:14
Bunuel
thankyou.

Posted from my mobile device
Intern
Intern
avatar
B
Joined: 09 Jan 2017
Posts: 3
CAT Tests
Re: M26-34  [#permalink]

Show Tags

New post 04 Nov 2018, 22:54
Hello,

in statement 1 if x=343 then square root of 7*343 is also an integer. but sq root of 343 is not an integer.

In which case statement 1 wont be sufficient.

Please clarify what I am missing?


Thanks
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 50585
Re: M26-34  [#permalink]

Show Tags

New post 04 Nov 2018, 22:58
ss9031 wrote:
Hello,

in statement 1 if x=343 then square root of 7*343 is also an integer. but sq root of 343 is not an integer.

In which case statement 1 wont be sufficient.

Please clarify what I am missing?


Thanks


From (1), as well as from (2), we got that \(\sqrt{x}\) cannot be an integer, the same answer you got.
_________________

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

GMAT Club Bot
Re: M26-34 &nbs [#permalink] 04 Nov 2018, 22:58
Display posts from previous: Sort by

M26-34

  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®.