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 350,000 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:

OA: C Explanation: To answer this question, you at the very least need the value of p; it would help to know something about m and n as well. Statement (1) is insuff; there are many possible prime number pairs that are 8 apart, and without knowing the value of p, we have no idea whether their sum is equal to p. Statement (2) is insuff: it's helpful to know that p = 50, but m and n could be 3 and 47, or they could be 3 and 5. In one case, the sum is equal to p; in the other, it isn't. Taken together, the statements are su¢ cient. The only pair of numbers that are 8 apart and sum to 50 are 21 and 29. 21 isn't a prime number, so whatever the values of m and n, they aren't 21 and 29. Thus, so long as m and n are 8 apart, they don't sum to 50, so their sum is not equal to p. (C) is the correct choice

OA: C Explanation: To answer this question, you at the very least need the value of p; it would help to know something about m and n as well. Statement (1) is insuff; there are many possible prime number pairs that are 8 apart, and without knowing the value of p, we have no idea whether their sum is equal to p. Statement (2) is insuff: it's helpful to know that p = 50, but m and n could be 3 and 47, or they could be 3 and 5. In one case, the sum is equal to p; in the other, it isn't. Taken together, the statements are su¢ cient. The only pair of numbers that are 8 apart and sum to 50 are 21 and 29. 21 isn't a prime number, so whatever the values of m and n, they aren't 21 and 29. Thus, so long as m and n are 8 apart, they don't sum to 50, so their sum is not equal to p. (C) is the correct choice

Given: \(p=integer>0\), \(m\) and \(n\) are prime numbers. Question: is \(m+n=50\)

(1) m - n = 8, clearly insufficient, as no info about p.

(2) p = 50 --> could 50 be the sum of 2 primes? Yes, 47+3=50. But m and n could be some other primes as well, which don't add up to 50, hence this statement is also not sufficient.

(1)+(2) \(m-n=8\) and \(p=50\). Let's assume that \(m+n=p=50\) is true. Then solving for m and n (2 equations \(m-n=8\) and \(m+n=50\)) we get that \(m=29\) and \(n=21\), but 21 is not prime number and we are given that \(n=prime\) hence our assumption that \(m+n={p}\) is false. So \(m+n\neq{p}\). Sufficient.

OA: C Explanation: To answer this question, you at the very least need the value of p; it would help to know something about m and n as well. Statement (1) is insuff; there are many possible prime number pairs that are 8 apart, and without knowing the value of p, we have no idea whether their sum is equal to p. Statement (2) is insuff: it's helpful to know that p = 50, but m and n could be 3 and 47, or they could be 3 and 5. In one case, the sum is equal to p; in the other, it isn't. Taken together, the statements are su¢ cient. The only pair of numbers that are 8 apart and sum to 50 are 21 and 29. 21 isn't a prime number, so whatever the values of m and n, they aren't 21 and 29. Thus, so long as m and n are 8 apart, they don't sum to 50, so their sum is not equal to p. (C) is the correct choice

Given: \(p=integer>0\), \(m\) and \(n\) are prime numbers. Question: is \(m+n=50\)

(1) m - n = 8, clearly insufficient, as no info about p.

(2) p = 50 --> could 50 be the sum of 2 primes? Yes, 47+3=50. But m and n could be some other primes as well, which don't add up to 50, hence this statement is also not sufficient.

(1)+(2) \(m-n=8\) and \(p=50\). Let's assume that \(m+n=p=50\) is true. Then solving for m and n (2 equations \(m-n=8\) and \(m+n=50\)) we get that \(m=29\) and \(n=21\), but 21 is not prime number and we are given that \(n=prime\) hence our assumption that \(m+n={p}\) is false. So \(m+n\neq{p}\). Sufficient.

Answer: C.

Bunuel Should not the question be is p=m+n? Why is the question is m+n=50?

"But m and n could be some other primes as well, which don't add up to 50, hence this statement is also not sufficient."

I am confused. By 2, we have p=50. If 47+3 is the ONLY combination of positive primes that gives us 50, then isn't 2 sufficient? You mention that there could be other primes that don't add up to 50 here, but then it is given that p=50. What am I missing? _________________

Re: Sum of Positive Primes [#permalink]
24 Aug 2010, 01:02

mainhoon wrote:

Bunuel Should not the question be is p=m+n? Why is the question is m+n=50?

"But m and n could be some other primes as well, which don't add up to 50, hence this statement is also not sufficient."

I am confused. By 2, we have p=50. If 47+3 is the ONLY combination of positive primes that gives us 50, then isn't 2 sufficient? You mention that there could be other primes that don't add up to 50 here, but then it is given that p=50. What am I missing?

Hi,

you're correct, the question is "does p = m + n?" Since (2) tells us that p=50, we can now substitute that value into the question to get a new question: "does 50 = m + n?"

However, since we have no idea what the actual values of m and n are, we're allowed to pick any primes.

So, if m=3 and n=47, then we ask "does 50 = 3 + 47?" and get the answer YES.

However, if m=5 and n=7, we ask "does 50 = 5 + 7?" and get the answer NO.

Since statement (2) can generate both a YES and a NO answer, it's insufficient.

Here's your error (a very common one in data sufficiency): you turned the question into a statement; in other words, to answer the question "is p = m + n?", you assumed that "p = m + n". _________________

How the growth of emerging markets will strain global finance : Emerging economies need access to capital (i.e., finance) in order to fund the projects necessary for...

One question I get a lot from prospective students is what to do in the summer before the MBA program. Like a lot of folks from non traditional backgrounds...