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

 It is currently 21 Jan 2019, 12:05

### 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

## Events & Promotions

###### Events & Promotions in January
PrevNext
SuMoTuWeThFrSa
303112345
6789101112
13141516171819
20212223242526
272829303112
Open Detailed Calendar
• ### GMAT Club Tests are Free & Open for Martin Luther King Jr.'s Birthday!

January 21, 2019

January 21, 2019

10:00 PM PST

11:00 PM PST

Mark your calendars - All GMAT Club Tests are free and open January 21st for celebrate Martin Luther King Jr.'s Birthday.
• ### The winners of the GMAT game show

January 22, 2019

January 22, 2019

10:00 PM PST

11:00 PM PST

In case you didn’t notice, we recently held the 1st ever GMAT game show and it was awesome! See who won a full GMAT course, and register to the next one.

# If x is an integer, is x even?

Author Message
TAGS:

### Hide Tags

Manager
Joined: 28 Jul 2011
Posts: 181
If x is an integer, is x even?  [#permalink]

### Show Tags

10 Sep 2015, 22:38
2
00:00

Difficulty:

45% (medium)

Question Stats:

56% (00:59) correct 44% (01:02) wrong based on 184 sessions

### HideShow timer Statistics

If x is an integer, is x even?

(1) x is equal to the difference between two consecutive prime numbers
(2) x is greater than 1
Manager
Joined: 28 Jul 2011
Posts: 181
Re: If x is an integer, is x even?  [#permalink]

### Show Tags

10 Sep 2015, 22:41
The question I have here is

(1) x is equal to the difference between two consecutive prime numbers

--> As far as i understand only consecutive prime numbers are 2 and 3.

Are 3 and 5 or 5 and 7 consecutive prime number?
CEO
Joined: 20 Mar 2014
Posts: 2636
Concentration: Finance, Strategy
Schools: Kellogg '18 (M)
GMAT 1: 750 Q49 V44
GPA: 3.7
WE: Engineering (Aerospace and Defense)
If x is an integer, is x even?  [#permalink]

### Show Tags

Updated on: 11 Sep 2015, 01:42
3
kuttingchai wrote:
The question I have here is

(1) x is equal to the difference between two consecutive prime numbers

--> As far as i understand only consecutive prime numbers are 2 and 3.

Are 3 and 5 or 5 and 7 consecutive prime number?

"Consecutive" prime numbers are prime numbers that have no other prime numbers between them.

So the list is :

2,3
3,5
5,7
7,11
11,13 etc

As for your question, is x = even?

Statement 1, x = |p1 - p2|, where p1 and p2 are consecutive prime numbers.

Now, if the 2 prime numbers are 2 and 3, you get x = odd-even = ODD, "no" to the question but if you choose any other set of consecutive prime numbers, you get x = odd - odd = even , "yes" to the question.

This statement is thus not sufficient.

Statement 2, x>1, again not helpful. Statement NOT sufficient.

Combining the statements you see that the possible values are

3-2 = 1, odd, ignored as statement 2 mentions that x>1
5-3 = 2, even
11-7 = 4, even etc

Thus, the only possible set of values for x are {2,4,...} and all of these are even. Thus x = even. C is the correct answer.

Originally posted by ENGRTOMBA2018 on 11 Sep 2015, 00:41.
Last edited by ENGRTOMBA2018 on 11 Sep 2015, 01:42, edited 1 time in total.
Updated the solution
Manager
Joined: 28 Jul 2011
Posts: 181
Re: If x is an integer, is x even?  [#permalink]

### Show Tags

11 Sep 2015, 01:31
Engr2012 wrote:
kuttingchai wrote:
The question I have here is

(1) x is equal to the difference between two consecutive prime numbers

--> As far as i understand only consecutive prime numbers are 2 and 3.

Are 3 and 5 or 5 and 7 consecutive prime number?

"Consecutive" prime numbers are prime numbers that have no other prime numbers between them.

So the list is :

2,3
3,5
5,7
7,11
11,13 etc

As for your question, is x = even?

Statement 1, x = |p1 - p2|, where p1 and p2 are consecutive prime numbers.

Now, if the 2 prime numbers are 2 and 3, you get x = odd-even = ODD, "no" to the question but if you choose any other set of consecutive prime numbers, you get x = odd - odd = even , "yes" to the question.

This statement is thus not sufficient.

Statement 2, x>1, again not helpful. Statement NOT sufficient.

Combining you see that statements do not provide any extra information and hence E should be the correct answer. kuttingchai Please check the OA. Had statement 2 been x>2, then you would have C as the correct answer.

OA is correct - C

Combined statement 1 and 2

we will have 5-3 = 2 or 7-5 = 2 or 13-11 = 2

3-2 =1 will not be considered as per statement 2.

C will be correct answer only when we say {3,2} {5,3} {7,5} are considered as consecutive prime numbers.

but, while reading on prime number in one of the reference book - I saw {3,2} is only consecutive prime numbers and {5,3} or {7,5} is not considered consecutive prime numbers. - This is the reason i got confused.

we don't consider {17,13} as consecutive prime numbers
CEO
Joined: 20 Mar 2014
Posts: 2636
Concentration: Finance, Strategy
Schools: Kellogg '18 (M)
GMAT 1: 750 Q49 V44
GPA: 3.7
WE: Engineering (Aerospace and Defense)
If x is an integer, is x even?  [#permalink]

### Show Tags

11 Sep 2015, 01:38
kuttingchai wrote:
Engr2012 wrote:
kuttingchai wrote:
The question I have here is

(1) x is equal to the difference between two consecutive prime numbers

--> As far as i understand only consecutive prime numbers are 2 and 3.

Are 3 and 5 or 5 and 7 consecutive prime number?

"Consecutive" prime numbers are prime numbers that have no other prime numbers between them.

So the list is :

2,3
3,5
5,7
7,11
11,13 etc

As for your question, is x = even?

Statement 1, x = |p1 - p2|, where p1 and p2 are consecutive prime numbers.

Now, if the 2 prime numbers are 2 and 3, you get x = odd-even = ODD, "no" to the question but if you choose any other set of consecutive prime numbers, you get x = odd - odd = even , "yes" to the question.

This statement is thus not sufficient.

Statement 2, x>1, again not helpful. Statement NOT sufficient.

Combining you see that statements do not provide any extra information and hence E should be the correct answer. kuttingchai Please check the OA. Had statement 2 been x>2, then you would have C as the correct answer.

OA is correct - C

Combined statement 1 and 2

we will have 5-3 = 2 or 7-5 = 2 or 13-11 = 2

3-2 =1 will not be considered as per statement 2.

C will be correct answer only when we say {3,2} {5,3} {7,5} are considered as consecutive prime numbers.

but, while reading on prime number in one of the reference book - I saw {3,2} is only consecutive prime numbers and {5,3} or {7,5} is not considered consecutive prime numbers. - This is the reason i got confused.

we don't consider {17,13} as consecutive prime numbers

Your definition of consecutive prime numbers is not correct. 2 prime numbers are considered consecutive if there are no prime numbers between them. 13 and 17 are consecutive prime numbers as there is no prime number between them.

This is from wikipedia: https://en.wikipedia.org/wiki/List_of_prime_numbers , in particular look at the table "The first 500 prime numbers"

Also, look at the question statement two-prime-numbers-are-considered-consecutive-if-no-other-prime-lies-be-205124.html especially the definition of "consecutive prime".

Additionally, knowing what do you mean by "consecutive prime numbers" is not required for answering this question. Look at my solution above.
Current Student
Joined: 12 Aug 2015
Posts: 2626
Schools: Boston U '20 (M)
GRE 1: Q169 V154
Re: If x is an integer, is x even?  [#permalink]

### Show Tags

20 Nov 2016, 23:48
Great Question
Here x is an integer .
WE need to check if x is even or not
Lets look at statements
Statement 1
Consecutive primes aren't just 2,3
Infact they can be 2,3 or 5,7 or 97,101 etc
Hence Insufficient
Statement 2
Here x>1
so x can be even or odd
Hence insufficient
Combining the two statements
we can say that x>1
so 2,3 are out of the equation
and rest primes are all odd(2 is the only even prime)
Hence x must be form odd-odd which is always even
hence sufficient to say that x must be always even

Hence C
_________________

MBA Financing:- INDIAN PUBLIC BANKS vs PRODIGY FINANCE!

Getting into HOLLYWOOD with an MBA!

The MOST AFFORDABLE MBA programs!

STONECOLD's BRUTAL Mock Tests for GMAT-Quant(700+)

AVERAGE GRE Scores At The Top Business Schools!

Manager
Joined: 22 May 2015
Posts: 108
Re: If x is an integer, is x even?  [#permalink]

### Show Tags

28 Dec 2017, 05:54
Given x is an integer. From

Statement 1)
Diff btw 2,3 is 1.
But since all other prime numbers are Odd, diff between 2 consecutive primes will always be Even and always >=2.
Insufficient.

Statement 2)
X is greater than 1.
Insufficient

Combining 1 and 2 we can definitely say x will always be even.
_________________

Consistency is the Key

Re: If x is an integer, is x even? &nbs [#permalink] 28 Dec 2017, 05:54
Display posts from previous: Sort by