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:

Each week we'll be posting several questions from The Official Guide For GMAT® Quantitative Review, 2ND Edition and then after couple of days we'll provide Official Answer (OA) to them along with a slution.

We'll be glad if you participate in development of this project: 1. Please provide your solutions to the questions; 2. Please vote for the best solutions by pressing Kudos button; 3. Please vote for the questions themselves by pressing Kudos button; 4. Please share your views on difficulty level of the questions, so that we have most precise evaluation.

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

Show Tags

12 Feb 2014, 02:14

2

This post received KUDOS

Expert's post

2

This post was BOOKMARKED

SOLUTION

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.

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 NONE of the odd integers 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 getdefinite 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.

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

Show Tags

12 Feb 2014, 03:02

2

This post received KUDOS

1

This post was BOOKMARKED

From 1: n>3 => put n=4 (Cannot be written), n=5 (can be written), Insufficient, A,D ruled out From 2: n= odd => put n=1(Cannot be written), n=5 (can be written), Insufficient, B ruled out Combining 1 &2 : n>3 and n is odd => sum of the primes is odd => one of the primes =2 Now, to rephrase this: the question asks "odd no. - 2 = prime ?" => maybe and may not be : C ruled out

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

Show Tags

17 Feb 2014, 02:27

Expert's post

SOLUTION

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.

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 NONE of the odd integers 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 getdefinite 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.

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

Show Tags

27 May 2014, 07:13

Bunuel wrote:

SOLUTION

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.

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 NONE of the odd integers 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 getdefinite 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.

Bunuel , is there any way to solve this question without putting values ?

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

Show Tags

04 Jun 2014, 06:37

I really don't like the word 'Can' in this question as it is not precise. Is there a chance that this would be a real GMAT question? I mean, I understand your explanation Bunuel, but you can actually answer the question with either statements. "Can it be?" - Sure it can, but also cannot, it depends on what the value of 'n' is.

Is that the way to approach this question? Ask yourself: "What is the value of n?" and if this is not given in the statements, then choose E?

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

Show Tags

04 Jun 2014, 08:50

1

This post received KUDOS

Expert's post

Saabs wrote:

I really don't like the word 'Can' in this question as it is not precise. Is there a chance that this would be a real GMAT question? I mean, I understand your explanation Bunuel, but you can actually answer the question with either statements. "Can it be?" - Sure it can, but also cannot, it depends on what the value of 'n' is.

Is that the way to approach this question? Ask yourself: "What is the value of n?" and if this is not given in the statements, then choose E?

This is OG question, so it's quite "real". _________________

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

Show Tags

16 Jun 2014, 08:03

Expert's post

sinhautkarsh wrote:

2 different prime numbers : We are ruling out option 'C' with an eg 11= 2+9 (9 is not prime)

However 11 = 2 +3 +3 = Sum of 2 different prime nos (2 and 3).based on this can we select C ...???

The question asks whether n can be written as the sum of two different prime numbers, so whether n = prime 1 + prime 2. If n = 11, then it cannot be written as the sum of two different primes. 2 + 3 + 3 + 3 cannot be said to be the sum of two primes, it's the sum of 4 numbers not 2. _________________

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

Show Tags

03 Oct 2015, 15:14

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 diff [#permalink]

Show Tags

03 Nov 2015, 02:43

Bunuel wrote:

SOLUTION

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.

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 NONE of the odd integers 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 getdefinite 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.

Hi Bunuel, I've 1 question regarding picking numbers for combined statement (1) + (2) Could we also pick following numbers here: ?? n=5 -> 3+2 Yes n=5 -> 4+1 No _________________

When you’re up, your friends know who you are. When you’re down, you know who your friends are.

Share some Kudos, if my posts help you. Thank you !

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

Show Tags

03 Nov 2015, 06:18

Expert's post

BrainLab wrote:

Bunuel wrote:

SOLUTION

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.

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 NONE of the odd integers 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 getdefinite 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.

Hi Bunuel, I've 1 question regarding picking numbers for combined statement (1) + (2) Could we also pick following numbers here: ?? n=5 -> 3+2 Yes n=5 -> 4+1 No

n=5 gives an YES answer to the question. 5 CAN be written as the sum of two difference prime numbers: 5 = 2 + 3.

While if n=11 or n=17 the answer would be NO. Neither 11 nor 17 can be written as the sum of two different prime numbers. _________________

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

Show Tags

03 Nov 2015, 21:46

I selected B because I took examples like 5 = 3+2, 9 = 7+2......19 = 17+2, Hence I thought that , it is possible to write using two prime numbers and data is sufficient.

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

Show Tags

08 Nov 2015, 05:43

Expert's post

Forget conventional ways of solving math questions. In DS, Variable approach is the easiest and quickest way to find the answer without actually solving the problem. Remember equal number of variables and independent equations ensures a solution.

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.

There is one variable (n) and 2 equations are given from the 2 conditions, so there is high chance (D) will be our answer. For condition 1, the answer is 'yes' for n=5=2+3, but 'no' for 23=2+21 For condition 2, the answer is 'yes' for n=5=2+3, but 'no' for 23=2+21 Looking at the conditions together, answer is 'yes' for n=5=2+3, but 'no' for 23=2+21. The answer is not unique; the answer becomes (E).

For cases where we need 1 more equation, such as original conditions with “1 variable”, or “2 variables and 1 equation”, or “3 variables and 2 equations”, we have 1 equation each in both 1) and 2). Therefore, there is 59 % chance that D is the answer, while A or B has 38% chance and C or E has 3% chance. Since D is most likely to be the answer using 1) and 2) separately according to DS definition. Obviously there may be cases where the answer is A, B, C or E. _________________

http://blog.ryandumlao.com/wp-content/uploads/2016/05/IMG_20130807_232118.jpg The GMAT is the biggest point of worry for most aspiring applicants, and with good reason. It’s another standardized test when most of us...

I recently returned from attending the London Business School Admits Weekend held last week. Let me just say upfront - for those who are planning to apply for the...