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.

It appears that you are browsing the GMAT Club forum unregistered!

Signing up is free, quick, and confidential.
Join other 500,000 members and get the full benefits of GMAT Club

Registration gives you:

Tests

Take 11 tests and quizzes from GMAT Club and leading GMAT prep companies such as Manhattan GMAT,
Knewton, and others. All are free for GMAT Club members.

Applicant Stats

View detailed applicant stats such as GPA, GMAT score, work experience, location, application
status, and more

Books/Downloads

Download thousands of study notes,
question collections, GMAT Club’s
Grammar and Math books.
All are free!

Thank you for using the timer!
We noticed you are actually not timing your practice. Click the START button first next time you use the timer.
There are many benefits to timing your practice, including:

Can the positive integer n be written as the sum of two [#permalink]

Show Tags

29 Jan 2012, 11:56

2

This post received KUDOS

4

This post was BOOKMARKED

00:00

A

B

C

D

E

Difficulty:

45% (medium)

Question Stats:

60% (01:30) correct
40% (00:55) wrong based on 319 sessions

HideShow timer Statistics

Can the positive integer n be written as the sum of two different positive prime numbers?

(1) n is greater than 3. (2) n is odd.

When I am checking the case using both conditions so can i rephrase problem statement as "Can every odd integer which is greater than 3 can be written as sum of two positive integers " OR "Can any odd integer which is greater than 3 can be written as sum of two positive integers"

90. Can the positive integer n be written as the sum of two different positive prime numbers? (1) n is greater than 3. (2) n is odd.

When I am checking the case using both conditions so can i rephrase problem statement as "Can every odd integer which is greater than 3 can be written as sum of two positive integers " OR "Can any odd integer which is greater than 3 can be written as sum of two positive integers"

Note that n is some particular, fixed number. If we take two statements together the question becomes: can odd integer n, which is greater than 3, be written as the sum of two different prime numbers?

Now, if EVERY odd integer greater than 3 can be written as the sum of two different prime numbers, then taken together statements would be sufficient as we get definite YES answer to the question (because if it can be done for EVERY odd integer greater than 3 then it can be done for some particular n, from this group, too). Also, if NEITHER odd integer greater than 3 can be written as the sum of two different prime numbers, then taken together statements would still be sufficient, though at this time we'd get definite NO answer to the question (because if it cannot be done for ANY odd integer greater than 3 then it can not be done for some particular n, from this group, too).

Next, if we can find two values of odd integer n greater than 3 and one of them can be written as the sum of two different prime numbers and another cannot, then taken together statements would NOT be sufficient.

For this question the answer is E: If n=5=odd>3, then the answer would be YES, 5=2+3=prime+prime; If n=11=odd>3, then the answer would be NO, (11=odd and in order it to be the sum of two different primes one must be 2=even=prime, in this case another number would be 9, since 9 is not a prime, you cannot write 11 as the sum of two different primes).

So, we have two values of odd integer n greater than 3: one of them can be written as the sum of two different prime numbers and another cannot, hence taken together statements are not sufficient.

90. Can the positive integer n be written as the sum of two different positive prime numbers? (1) n is greater than 3. (2) n is odd.

When I am checking the case using both conditions so can i rephrase problem statement as "Can every odd integer which is greater than 3 can be written as sum of two positive integers " OR "Can any odd integer which is greater than 3 can be written as sum of two positive integers"

Note that n is some particular, fixed number. If we take two statements together the question becomes: can odd integer n, which is greater than 3, be written as the sum of two different prime numbers?

Now, if EVERY odd integer greater than 3 can be written as the sum of two different prime numbers, then taken together statements would be sufficient as we get definite YES answer to the question (because if it can be done for EVERY odd integer greater than 3 then it can be done for some particular n, from this group, too). Also, if NEITHER odd integer greater than 3 can be written as the sum of two different prime numbers, then taken together statements would still be sufficient, though at this time we'd get definite NO answer to the question (because if it cannot be done for ANY odd integer greater than 3 then it can not be done for some particular n, from this group, too).

Next, if we can find two values of odd integer n greater than 3 and one of them can be written as the sum of two different prime numbers and another cannot, then taken together statements would NOT be sufficient.

For this question the answer is E: If n=5=odd>3, then the answer would be YES, 5=2+3=prime+prime; If n=11=odd>3, then the answer would be NO, (11=odd and in order it to be the sum of two different primes one must be 2=even=prime, in this case another number would be 9, since 9 is not a prime, you cannot write 11 as the sum of two different primes).

So, we have two values of odd integer n greater than 3: one of them can be written as the sum of two different prime numbers and another cannot, hence taken together statements are not sufficient.

Answer: E.

Hope it's clear.

solved it correctly but could not find a clear takeaway for this problem
_________________

Re: Can the positive integer n be written as the sum of two [#permalink]

Show Tags

14 Mar 2013, 22:50

1

This post received KUDOS

monikaleoster wrote:

Can the positive integer n be written as the sum of two different positive prime numbers?

(1) n is greater than 3. (2) n is odd.

Nothing new to add after Bunuel's explanation. But just to point down what I observed for F.S 2;we know that n is odd. Again we have been asked if n is a sum of 2 different primes. Now we know that only odd+even = odd. Thus out of the two given prime numbers, we can have only 2 as the even prime. So now the statement basically states that if we subtract 2 from n, do we end up with a prime greater than 2.

or Is n-2 = a prime greater than 2. Take any odd integer for n. For n=13, we get a YES. For n=17, we get a NO. Insufficient.
_________________

Re: Can the positive integer n be written as the sum of two [#permalink]

Show Tags

16 Mar 2013, 14:08

vinaymimani wrote:

monikaleoster wrote:

Can the positive integer n be written as the sum of two different positive prime numbers?

(1) n is greater than 3. (2) n is odd.

Nothing new to add after Bunuel's explanation. But just to point down what I observed for F.S 2;we know that n is odd. Again we have been asked if n is a sum of 2 different primes. Now we know that only odd+even = odd. Thus out of the two given prime numbers, we can have only 2 as the even prime. So now the statement basically states that if we subtract 2 from n, do we end up with a prime greater than 2.

or Is n-2 = a prime greater than 2. Take any odd integer for n. For n=13, we get a YES. For n=17, we get a NO. Insufficient.

Good explanation!

I almost read n to be one of the numbers and did a mental calculation to arrive at C. But, now i am clear!
_________________

Re: Can the positive integer n be written as the sum of two [#permalink]

Show Tags

02 Sep 2015, 02:07

Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________

Re: Can the positive integer n be written as the sum of two [#permalink]

Show Tags

16 Mar 2016, 12:11

Hi Guys, I am not a native speaker and I am confused by the question - should I read it as "Is the positive integer n represents the sum of two different positive prime numbers?"

Hi Guys, I am not a native speaker and I am confused by the question - should I read it as "Is the positive integer n represents the sum of two different positive prime numbers?"

Thanks!

No. It means is it possible to write positive integer n as the sum of two different positive prime numbers.
_________________

Version 8.1 of the WordPress for Android app is now available, with some great enhancements to publishing: background media uploading. Adding images to a post or page? Now...

“Keep your head down, and work hard. Don’t attract any attention. You should be grateful to be here.” Why do we keep quiet? Being an immigrant is a constant...

“Keep your head down, and work hard. Don’t attract any attention. You should be grateful to be here.” Why do we keep quiet? Being an immigrant is a constant...