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

It is currently 18 Oct 2019, 11:56

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

Is x an integer? (1) The average (arithmetic mean) of x – 1 and x +

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

Hide Tags

Find Similar Topics 
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 58453
Is x an integer? (1) The average (arithmetic mean) of x – 1 and x +  [#permalink]

Show Tags

New post 09 Jan 2018, 23:32
00:00
A
B
C
D
E

Difficulty:

  45% (medium)

Question Stats:

54% (01:14) correct 46% (01:23) wrong based on 45 sessions

HideShow timer Statistics

Retired Moderator
avatar
P
Joined: 22 Aug 2013
Posts: 1428
Location: India
Re: Is x an integer? (1) The average (arithmetic mean) of x – 1 and x +  [#permalink]

Show Tags

New post 10 Jan 2018, 00:11
Bunuel wrote:
Is x an integer?

(1) The average (arithmetic mean) of x – 1 and x + 1 is an integer.
(2) The average (arithmetic mean) of x and –x is an integer.


(1) Average of x-1 and x+1 is = (x-1 + x+1)/2 = 2x/2 = x, which is given to be an integer. So x is an integer. Sufficient.

(2) Average of x and -x is = (x - x)/2 = 0/2 = 0. Whatever be the value of x (integer or non-integer), sum of x and -x will always be 0, and thus average will also be 0. So we cant say whether x is an integer or not based on this information. Insufficient.

Hence A answer
Intern
Intern
avatar
B
Joined: 09 Jul 2017
Posts: 30
Re: Is x an integer? (1) The average (arithmetic mean) of x – 1 and x +  [#permalink]

Show Tags

New post 10 Jan 2018, 11:43
X could be a decimal also right ? Will A be the sufficient answer ?


Sent from my iPhone using GMAT Club Forum
Director
Director
avatar
P
Joined: 31 Jul 2017
Posts: 512
Location: Malaysia
Schools: INSEAD Jan '19
GMAT 1: 700 Q50 V33
GPA: 3.95
WE: Consulting (Energy and Utilities)
Re: Is x an integer? (1) The average (arithmetic mean) of x – 1 and x +  [#permalink]

Show Tags

New post 10 Jan 2018, 20:37
Bunuel wrote:
Is x an integer?

(1) The average (arithmetic mean) of x – 1 and x + 1 is an integer.
(2) The average (arithmetic mean) of x and –x is an integer.


Stmnt 1: Let X = 1.. we get average as Integer, let x = 1/2 we get average as Integer.. So not suffiecient.
Stmn 2: X = 1, Average Integer... X = 1/2, Average = Integer

So E.
_________________
If my Post helps you in Gaining Knowledge, Help me with KUDOS.. !!
Intern
Intern
avatar
B
Joined: 22 Nov 2017
Posts: 25
Location: United States
Concentration: Technology, Healthcare
GMAT ToolKit User
Re: Is x an integer? (1) The average (arithmetic mean) of x – 1 and x +  [#permalink]

Show Tags

New post 10 Jan 2018, 21:12
Average of x-1 and x+1 is X which is given to be an integer so X is an integer so sufficient. Statement 2 the average is 0 which does not give any idea abt X. So not sufficient. So answer is A.

Sent from my SAMSUNG-SM-J120A using GMAT Club Forum mobile app
Math Expert
avatar
V
Joined: 02 Aug 2009
Posts: 7978
Re: Is x an integer? (1) The average (arithmetic mean) of x – 1 and x +  [#permalink]

Show Tags

New post 10 Jan 2018, 21:30
rahul16singh28 wrote:
Bunuel wrote:
Is x an integer?

(1) The average (arithmetic mean) of x – 1 and x + 1 is an integer.
(2) The average (arithmetic mean) of x and –x is an integer.


Stmnt 1: Let X = 1.. we get average as Integer, let x = 1/2 we get average as Integer.. So not suffiecient.
Stmn 2: X = 1, Average Integer... X = 1/2, Average = Integer

So E.


I
Average of x-1 and x+1 is nothing but x itself and it is given as integer, so x is integer..
average of x-1 and x+1 is \(\frac{x-1+x+1}{2}=\frac{2x}{2}=x\)
so statement I is suff..

II
Whatever be value of x, the average of x and -x should be 0
so statement II does not tell anything new
insuff

A
_________________
Intern
Intern
avatar
B
Joined: 22 Nov 2017
Posts: 25
Location: United States
Concentration: Technology, Healthcare
GMAT ToolKit User
Re: Is x an integer? (1) The average (arithmetic mean) of x – 1 and x +  [#permalink]

Show Tags

New post 10 Jan 2018, 21:38
Average is 0 in statement 2 and not the value of x. X can be integer or non integer the average of X and -x is always 0. So it doesnt say the type of X

Sent from my SAMSUNG-SM-J120A using GMAT Club Forum mobile app
Retired Moderator
avatar
P
Joined: 22 Aug 2013
Posts: 1428
Location: India
Re: Is x an integer? (1) The average (arithmetic mean) of x – 1 and x +  [#permalink]

Show Tags

New post 10 Jan 2018, 22:43
akhilbatra06 wrote:
Zero is an integer


Sent from my iPhone using GMAT Club Forum


Hi

Yes, zero is an integer. So average of x and -x will be 0, which is an integer. If x=2, then also average of x and -x is zero. If x=1.5, then also average of x and -x is zero.
So zero being an integer doesnt tell us anything whether x will be an integer or not. '

So answer should be A.
GMAT Club Bot
Re: Is x an integer? (1) The average (arithmetic mean) of x – 1 and x +   [#permalink] 10 Jan 2018, 22:43
Display posts from previous: Sort by

Is x an integer? (1) The average (arithmetic mean) of x – 1 and x +

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





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