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

 It is currently 22 Oct 2019, 20:39 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

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.  Is x even? (1) x^5 is even. (2) 4x – 2 is even.

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

Hide Tags

Math Expert V
Joined: 02 Sep 2009
Posts: 58427
Is x even? (1) x^5 is even. (2) 4x – 2 is even.  [#permalink]

Show Tags

2
2 00:00

Difficulty:   65% (hard)

Question Stats: 15% (01:08) correct 85% (00:43) wrong based on 86 sessions

HideShow timer Statistics

Is x even?

(1) x^5 is even.
(2) 4x – 2 is even.

_________________
Senior Manager  G
Joined: 06 Jul 2016
Posts: 358
Location: Singapore
Concentration: Strategy, Finance
Re: Is x even? (1) x^5 is even. (2) 4x – 2 is even.  [#permalink]

Show Tags

A) is the answer.

As 2) will always be even regardless of the value of x so it's not sufficient IMO

Posted from my mobile device
_________________
Put in the work, and that dream score is yours!
VP  D
Joined: 05 Mar 2015
Posts: 1000
Is x even? (1) x^5 is even. (2) 4x – 2 is even.  [#permalink]

Show Tags

2
Bunuel wrote:
Is x even?

(1) x^5 is even.
(2) 4x – 2 is even.

(1) if x= 2^1/5 then X^5= 2 thus x is not even
IF x=2 then x^5=32 thus X is even

Not suff

(2) if x=3 then 4x – 2 = 10 even thus x =odd
if x=2 then 4x – 2 = 6 even thus x=even
Not suff

combining both
we know x must be integer
thus from (1) x must be even(as odd^x = odd)

Ans C
Math Expert V
Joined: 02 Aug 2009
Posts: 8011
Is x even? (1) x^5 is even. (2) 4x – 2 is even.  [#permalink]

Show Tags

1
Bunuel wrote:
Is x even?

(1) x^5 is even.
(2) 4x – 2 is even.

With almost 100% going wrong in a sub-600 level question shows that we tend to overlook number properties at many times..
(1) $$x^5$$ is even.
If x is an integer, yes x is even..
But if x is not an integer
$$x=\sqrt{2}$$.. $$x^5 is even but x is NOT Insuff$$

(2) $$4x – 2$$ is even
$$4x-2=2(2x-1)$$
so x could be any integer, 1,2, or even fraction 1.5,2.5...
insuff

combined..
statement II gives x as an integer and statement I says if x is integer, x is even..
sufficient

C
_________________
Intern  Joined: 06 Jan 2018
Posts: 7
Re: Is x even? (1) x^5 is even. (2) 4x – 2 is even.  [#permalink]

Show Tags

1-Since x is not necessarily an integer, then it is easy to prove x could either be even (2^5 = 32, but (2^(1/5))^5 = 2, but x is not even
Not suff

2- 4x-2 is even. X could be even (2) or x could not be even (i.e. 0.5)
Not suff

1,2 combined will be satisfied since x would have to be an integer in this case... then C will be the answer

Great question!!!!!

Sent from my iPhone using GMAT Club Forum Re: Is x even? (1) x^5 is even. (2) 4x – 2 is even.   [#permalink] 25 Jan 2018, 23:06
Display posts from previous: Sort by

Is x even? (1) x^5 is even. (2) 4x – 2 is even.

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

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