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

It is currently 07 Dec 2019, 09:29

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

If n is any prime number greater than 2, which of the following CANNOT

  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: 59588
If n is any prime number greater than 2, which of the following CANNOT  [#permalink]

Show Tags

New post 03 Jul 2018, 01:49
00:00
A
B
C
D
E

Difficulty:

  55% (hard)

Question Stats:

50% (01:05) correct 50% (01:16) wrong based on 92 sessions

HideShow timer Statistics

VP
VP
User avatar
D
Joined: 31 Oct 2013
Posts: 1491
Concentration: Accounting, Finance
GPA: 3.68
WE: Analyst (Accounting)
CAT Tests
If n is any prime number greater than 2, which of the following CANNOT  [#permalink]

Show Tags

New post Updated on: 03 Jul 2018, 02:52
Bunuel wrote:
If n is any prime number greater than 2, which of the following CANNOT be a prime number?

A. n-4
B. n-3
C. n-1
D. n+2
E. n+5


Note: n> 2 . all prime.

We have to find out the option that can't be prime.

It's given that m is a prime greater than 2. Some one can scan the answer choices.

**** Option E that us even integer all time for any prime greater than 2. ***** only even that is prime is 2. but it is impossible here.

The best answer is E.

Originally posted by KSBGC on 03 Jul 2018, 02:00.
Last edited by KSBGC on 03 Jul 2018, 02:52, edited 1 time in total.
Director
Director
User avatar
G
Joined: 20 Feb 2015
Posts: 737
Concentration: Strategy, General Management
Re: If n is any prime number greater than 2, which of the following CANNOT  [#permalink]

Show Tags

New post 03 Jul 2018, 02:45
Bunuel wrote:
If n is any prime number greater than 2, which of the following CANNOT be a prime number?

A. n-4
B. n-3
C. n-1
D. n+2
E. n+5



2 is the only even prime number
any number greater than 2 has to be an odd number to be considered as a prime number

if n is prime n-1 will always be even
therefore ,
C can never be a prime number
VP
VP
User avatar
D
Joined: 31 Oct 2013
Posts: 1491
Concentration: Accounting, Finance
GPA: 3.68
WE: Analyst (Accounting)
CAT Tests
If n is any prime number greater than 2, which of the following CANNOT  [#permalink]

Show Tags

New post Updated on: 03 Jul 2018, 03:05
CounterSniper wrote:
Bunuel wrote:
If n is any prime number greater than 2, which of the following CANNOT be a prime number?

A. n-4
B. n-3
C. n-1
D. n+2
E. n+5



2 is the only even prime number
any number greater than 2 has to be an odd number to be considered as a prime number

if n is prime n-1 will always be even
therefore ,
C can never be a prime number



what if n = 3

n-1 = 3-1 = 2

question make told us that n> 2. but he doesn't tell us that result must be greater that 2 . thanks.

Originally posted by KSBGC on 03 Jul 2018, 02:51.
Last edited by KSBGC on 03 Jul 2018, 03:05, edited 1 time in total.
Director
Director
User avatar
G
Joined: 20 Feb 2015
Posts: 737
Concentration: Strategy, General Management
Re: If n is any prime number greater than 2, which of the following CANNOT  [#permalink]

Show Tags

New post 03 Jul 2018, 02:55
selim wrote:
CounterSniper wrote:
Bunuel wrote:
If n is any prime number greater than 2, which of the following CANNOT be a prime number?

A. n-4
B. n-3
C. n-1
D. n+2
E. n+5



2 is the only even prime number
any number greater than 2 has to be an odd number to be considered as a prime number

if n is prime n-1 will always be even
therefore ,
C can never be a prime number



what if n = 3

n-1 = 3-1 = 2


Should be greater than 2
Senior Manager
Senior Manager
User avatar
G
Joined: 29 Dec 2017
Posts: 374
Location: United States
Concentration: Marketing, Technology
GMAT 1: 630 Q44 V33
GMAT 2: 690 Q47 V37
GMAT 3: 710 Q50 V37
GPA: 3.25
WE: Marketing (Telecommunications)
Re: If n is any prime number greater than 2, which of the following CANNOT  [#permalink]

Show Tags

New post 03 Jul 2018, 05:58
CounterSniper wrote:
Should be greater than 2


CounterSniper

n has to be greater than 2, but n-1 can be any number (prime). Thus when n=3, n-1=2 - prime. The answer is E
Director
Director
User avatar
G
Joined: 20 Feb 2015
Posts: 737
Concentration: Strategy, General Management
If n is any prime number greater than 2, which of the following CANNOT  [#permalink]

Show Tags

New post 04 Jul 2018, 04:34
Hero8888 wrote:
CounterSniper wrote:
Should be greater than 2


CounterSniper

n has to be greater than 2, but n-1 can be any number (prime). Thus when n=3, n-1=2 - prime. The answer is E



My Bad !! should read the question more carefully !!
n > 2 must always be odd
all except E can be prime numbers , as odd+odd=even and even no > 2 can never be prime !!
Senior Manager
Senior Manager
User avatar
P
Status: Gathering chakra
Joined: 05 Feb 2018
Posts: 440
Premium Member
Re: If n is any prime number greater than 2, which of the following CANNOT  [#permalink]

Show Tags

New post 06 Feb 2019, 06:47
Bunuel wrote:
If n is any prime number greater than 2, which of the following CANNOT be a prime number?

A. n-4
B. n-3
C. n-1
D. n+2
E. n+5


The longer way would be to plug in numbers of small primes:
A) 7-4=3, prime
B) 5-3=2, prime
C) 3-1=2, prime
D) 3+2=5, prime
E) only answer left

The shorter way: realize that all primes except 2 and 5 end in either 1, 3, 7 or 9. n>2, so if we add 5 to any of those besides 2 we get an even number (e.g. 6, 8, 10, 12, 14).
GMAT Club Bot
Re: If n is any prime number greater than 2, which of the following CANNOT   [#permalink] 06 Feb 2019, 06:47
Display posts from previous: Sort by

If n is any prime number greater than 2, which of the following CANNOT

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





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