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

It is currently 11 Dec 2018, 06:04

R1 Decisions:

HBS Chat - Decisions will be released at Noon ET  |  UVA Darden Chat  |  YouTube Live with Cornell Johnson @11am ET


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
  • Free GMAT Prep Hour

     December 11, 2018

     December 11, 2018

     09:00 PM EST

     10:00 PM EST

    Strategies and techniques for approaching featured GMAT topics. December 11 at 9 PM EST.
  • The winning strategy for 700+ on the GMAT

     December 13, 2018

     December 13, 2018

     08:00 AM PST

     09:00 AM PST

    What people who reach the high 700's do differently? We're going to share insights, tips and strategies from data we collected on over 50,000 students who used examPAL.

Is C square of an Integer? 1) Sum of the factors of integer C is ODD

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

Hide Tags

CEO
CEO
User avatar
P
Status: GMATINSIGHT Tutor
Joined: 08 Jul 2010
Posts: 2710
Location: India
GMAT: INSIGHT
WE: Education (Education)
Reviews Badge
Is C square of an Integer? 1) Sum of the factors of integer C is ODD  [#permalink]

Show Tags

New post 27 Apr 2018, 00:46
00:00
A
B
C
D
E

Difficulty:

  75% (hard)

Question Stats:

49% (01:52) correct 51% (01:44) wrong based on 58 sessions

HideShow timer Statistics

Is C square of an Integer?

1) Sum of the factors of integer C is ODD
2) Number of distinct factors of Integer C is ODD

Source: www.GMATinsight.com

_________________

Prosper!!!
GMATinsight
Bhoopendra Singh and Dr.Sushma Jha
e-mail: info@GMATinsight.com I Call us : +91-9999687183 / 9891333772
Online One-on-One Skype based classes and Classroom Coaching in South and West Delhi
http://www.GMATinsight.com/testimonials.html

ACCESS FREE GMAT TESTS HERE:22 ONLINE FREE (FULL LENGTH) GMAT CAT (PRACTICE TESTS) LINK COLLECTION

Manager
Manager
User avatar
B
Joined: 05 Dec 2017
Posts: 52
Location: India
Concentration: Finance, International Business
WE: Analyst (Commercial Banking)
GMAT ToolKit User
Re: Is C square of an Integer? 1) Sum of the factors of integer C is ODD  [#permalink]

Show Tags

New post 27 Apr 2018, 01:06
GMATinsight wrote:
Is C square of an Integer?

1) Sum of the factors of integer C is ODD
2) Number of distinct factors of Integer C is ODD

Source: http://www.GMATinsight.com


St1 : Sum of the factors of integer C is ODD

Factors of 9 = 1, 3, 9; so sum : ODD
Factors of 8 = 1, 2, 4, 8 Sum : ODD

Hence statement 1 insuff

St2 : Number of distinct factors of Integer C is ODD
For a int N = \(x^ay^b..\) the number of factors are \((a+1)*(b+1)...\)
So if \((a+1)*(b+1)...\) is odd, this means each \((a+1), (b+1),...\) is odd

or A, B,... are even
Hence the number \(N = x^{even}*Y^{even}...\)

So We can say Number is square of number.

Hence Option B
PS Forum Moderator
User avatar
P
Status: It always seems impossible until it's done.
Joined: 16 Sep 2016
Posts: 413
GMAT 1: 740 Q50 V40
GMAT ToolKit User Premium Member Reviews Badge CAT Tests
Re: Is C square of an Integer? 1) Sum of the factors of integer C is ODD  [#permalink]

Show Tags

New post 27 Apr 2018, 02:34
GMATinsight wrote:
Is C square of an Integer?

1) Sum of the factors of integer C is ODD
2) Number of distinct factors of Integer C is ODD

Source: http://www.GMATinsight.com


Let us try to solve this by trying numbers :

let n = 4. we know n is a square of integer 2.

1) Sum of the factors of integer C is ODD. Not sufficient 1 + 2 + 4 = 7 ( true for 4) 1 + 2 + 3 + 4 + 6 + 9 + 12 + 18 + 36 = 91 ( true for 36) 1 + 17 + 289 ( true for 289 ).
Although it is true for perfect squares, it is also true for other which are not perfect squares

ex. 1 + 2 + 4 + 8 = 15 ( also true for 8)

2) Number of distinct factors of Integer C is ODD Suff this is a property which is easily seen to be true. all the factors will pair out and the perfect square will remain. look at the factors of 36 to verify this

Hence Option (B) is our answer.

Best,
Gladi
Intern
Intern
avatar
B
Joined: 16 Aug 2018
Posts: 28
Concentration: General Management, Strategy
Schools: Guanghua"21 (A)
GMAT 1: 700 Q49 V36
Re: Is C square of an Integer? 1) Sum of the factors of integer C is ODD  [#permalink]

Show Tags

New post 22 Aug 2018, 16:55
statement 1:
we can only infer that no. of odd prime factors is odd but we don't know the no. of even prime factor (2):
eg. 3^2*2^3 has 3 odd factors and 9 even factors but the sum of the factors is odd
3^2*2^4 has 3 odd factors and 12 even factors but the sum of the factors is still odd
statement 2:
assume C=A^a*B^b*E^e
no. of factors: (a+1)(b+1)(c+1)
a,b,e all have to be even no. to have odd no. of distince factors. hence C is a squre
GMAT Club Bot
Re: Is C square of an Integer? 1) Sum of the factors of integer C is ODD &nbs [#permalink] 22 Aug 2018, 16:55
Display posts from previous: Sort by

Is C square of an Integer? 1) Sum of the factors of integer C is ODD

  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®.