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:

Re: If N, C, and D are positive integers, what is the remainder [#permalink]

Show Tags

06 Nov 2012, 18:54

1. insufficient b/c D and C can be any number. adding +1 can change remainder completely. ex: D =2 , C = 3 R = 2 ... D = 2+1 , C = 3+1 R = 3 2: sufficient b/c (ND + NC)/CN => ND/CN + NC/CN => ND/CN =>D/C + 1 => R5

Re: If N, C, and D are positive integers, what is the remainder [#permalink]

Show Tags

14 Oct 2014, 13:11

1) insufficient 2) ND+NC/CN gives a remainder of 5.

ND + NC / CN = (D+C)/C

So we know that (D+C)/C gives a remainder of 5.

The idea here is that if you add any multiple of C to C then you will definitely get a multiple of C. For eg. 4 is a multiple of 2. So (4+2)/2 will give R=0. In this case though we have a number added to C leaving a remainder of 5. This means that D is not divisible by C and that D must leave a remainder of 5. Eg. (5+0)/10 leaves a remainder of 5 . (5+10)/10 will leave a remainder of 5 also. So the remainder will always be in D in the equation (D+C). This means that D/C will also give us a remainder of 5. Sufficient.

Re: If N, C, and D are positive integers, what is the remainder [#permalink]

Show Tags

28 Oct 2014, 12:10

Well, I am confused here and need some help.

I chose D.

Reason is as follows: For statement A: take D+1=12 and C+1=7 so 12/7 => remainder 5 if we take 11/6 => remainder is still 5

In the explanation above for D=CK + (K + 4), for different values of K, we are actually changing the value of D while keeping the value of C same. If the algebra calculations are correct and logic is correct, there must be some example to support this explanation.

Re: If N, C, and D are positive integers, what is the remainder [#permalink]

Show Tags

04 Nov 2014, 02:55

VeritasPrepKarishma wrote:

kingb wrote:

If N, C, and D are positive integers, what is the remainder when D is divided by C?

1) If D+1 is divided by C+1, the remainder is 5. 2) If ND+NC is divided by CN, the remainder is 5.

Stmnt 1: If D+1 is divided by C+1, the remainder is 5.

D+1 = (C+1)k + 5 D = Ck + (k + 4) When D is divided by C, the remainder will vary with k. If k = 0, remainder will be 4 (C is greater than 4) If k = 1, remainder will be 5 (C is greater than 5) If k = 2, remainder will be 6 (C is greater than 6) etc

2) If ND+NC is divided by CN, the remainder is 5. ND + NC = CN*k + 5 DN = CN*(k-1) + 5 D = C*(k-1) + 5/N Now, N is a positive integer and remainder must be a positive integer too. The only value that N can take such that 5/N is a positive integer is 1. So N must be 1. D = C*(k -1) + 5 When D is divided by C, remainder is 5.

Answer (B)

Sorry to bother , I just want to ask ... N can't be 5 ? 5/N will still be integer i.e. 1 Could you please explain why only value N can take is 1?

If N, C, and D are positive integers, what is the remainder when D is divided by C?

1) If D+1 is divided by C+1, the remainder is 5. 2) If ND+NC is divided by CN, the remainder is 5.

Stmnt 1: If D+1 is divided by C+1, the remainder is 5.

D+1 = (C+1)k + 5 D = Ck + (k + 4) When D is divided by C, the remainder will vary with k. If k = 0, remainder will be 4 (C is greater than 4) If k = 1, remainder will be 5 (C is greater than 5) If k = 2, remainder will be 6 (C is greater than 6) etc

2) If ND+NC is divided by CN, the remainder is 5. ND + NC = CN*k + 5 DN = CN*(k-1) + 5 D = C*(k-1) + 5/N Now, N is a positive integer and remainder must be a positive integer too. The only value that N can take such that 5/N is a positive integer is 1. So N must be 1. D = C*(k -1) + 5 When D is divided by C, remainder is 5.

Answer (B)

Sorry to bother , I just want to ask ... N can't be 5 ? 5/N will still be integer i.e. 1 Could you please explain why only value N can take is 1?

Actually it can take value 5 too. I will rewrite the solution given above soon.
_________________

Reason is as follows: For statement A: take D+1=12 and C+1=7 so 12/7 => remainder 5 if we take 11/6 => remainder is still 5

In the explanation above for D=CK + (K + 4), for different values of K, we are actually changing the value of D while keeping the value of C same. If the algebra calculations are correct and logic is correct, there must be some example to support this explanation.

We all agree to sufficiency of statement B.

Please advise.

In statement 1, say if C+1 = 8 and D+1 = 21, remainder is 5. C = 7 and D = 20, remainder is 6. Not sufficient alone.
_________________

Re: If N, C, and D are positive integers, what is the remainder [#permalink]

Show Tags

15 Sep 2016, 00:19

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.
_________________

OA is definitely wrong. Should be E. you cannot write remainder(ND/NC) = remainder(D/C)

eg remainder(20/15) = 5, remainder(4/3) = 1

I agree. Let me expand this out to show the actual cases that prove insufficiency.

(1) case 1: D = 19, C = 14. Obeys the statement, because when 20 is divided by 15, the remainder is 5. The answer to the question is also 5. case 2: D = 28, C = 5. Obeys, the statement, because when 29 is divided by 6, the remainder is 5. The answer to the question, though, is 3. That's because when you divide 28 by 5, the remainder is 3.

(2) case 1: D = 4, C = 3, N = 5. Obeys the statement, because when 20 + 15 is divided by 15, the remainder is 5. The answer to the question is 1. case 2: D = 20, C = 15, N = 1. Obeys the statement, because when 20+15 is divided by 15, the remainder is 5. The answer to the question, however, is 5.

We have two different possible answers to the question for statement 1, and two different possible answers for statement 2. Now let's put them together.

(1+2) case 1: D = 19, C = 14, N = 1. - Obeys statement 1 (we already tested it). - It also obeys statement 2, because when 19 + 14 is divided by 14, the remainder is 5. - The answer to the question is 5.

case 2: D = 25, C = 6, N = 5. - Obeys statement 1: 26 divided by 7 has a remainder of 5. - Obeys statement 2: 125 divided by 30 has a remainder of 5. - The answer to the question is 1.

So, the answer is (E).

That said, on the test, I would work on this one for about 90 seconds and then guess either C or E.
_________________

Chelsey Cooley | Manhattan Prep Instructor | Seattle and Online

Hey, guys, So, I’ve decided to run a contest in hopes of getting the word about the site out to as many applicants as possible this application season...

Whether you’re an entrepreneur, aspiring business leader, or you just think that you may want to learn more about business, the thought of getting your Masters in Business Administration...

Whether you’re an entrepreneur, aspiring business leader, or you just think that you may want to learn more about business, the thought of getting your Masters in Business Administration...