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:

If S is the infinite sequence: S1=9, S2=99, S3=999, ..., SK = 10^K-1, ..., is every term in S divisible by the prime number p?

(1) p is greater than 2.

(2) At least one term in sequence S is divisible by p.

I think with statement 2 - if P is 3 then all the terms in the sequence are divisible by P So my answer is B

Please advise.

No, B is not correct. It's straight E: if p=3 then every term in S is divisible by p but if p=11 then some terms in S are divisible by p (for example 99 and 9999) and some are not (for example 9 and 999). Not sufficient.

If you were to test examples to satisfy the equations what would they be examples for each statement.

Since the answer is E, then the examples given in my post to show that the two statements taken together are not sufficient to answer the question, would also serve to discard each statement.
_________________

Re: If S is the infinite sequence S1=9 S2=99 S3=999 SK=10^k-1 [#permalink]

Show Tags

22 Dec 2013, 07:01

Bunuel wrote:

morya003 wrote:

If S is the infinite sequence: S1=9, S2=99, S3=999, ..., SK = 10^K-1, ..., is every term in S divisible by the prime number p?

(1) p is greater than 2.

(2) At least one term in sequence S is divisible by p.

No, B is not correct. It's straight E: if p=3 then every term in S is divisible by p but if p=11 then some terms in S are divisible by p (for example 99 and 9999) and some are not (for example 9 and 999). Not sufficient.

Answer: E.

hope it's clear.

Hello Bunuel

I have a doubt here. Since we know after combining the 2 statements that the Prime number will NOT be 3 but any other Prime number that divides at least 1 number in the sequence. So now we know for SURE that EVERY TERM IS NOT Divisible by a particular Prime number( Which the Questions asks). 11 will also not divide all terms but few only.

SO should the Answer not be "C" ? Please correct me.

If S is the infinite sequence: S1=9, S2=99, S3=999, ..., SK = 10^K-1, ..., is every term in S divisible by the prime number p?

(1) p is greater than 2.

(2) At least one term in sequence S is divisible by p.

No, B is not correct. It's straight E: if p=3 then every term in S is divisible by p but if p=11 then some terms in S are divisible by p (for example 99 and 9999) and some are not (for example 9 and 999). Not sufficient.

Answer: E.

hope it's clear.

Hello Bunuel

I have a doubt here. Since we know after combining the 2 statements that the Prime number will NOT be 3 but any other Prime number that divides at least 1 number in the sequence. So now we know for SURE that EVERY TERM IS NOT Divisible by a particular Prime number( Which the Questions asks). 11 will also not divide all terms but few only.

SO should the Answer not be "C" ? Please correct me.

Re: If S is the infinite sequence S1=9 S2=99 S3=999 SK=10^k-1 [#permalink]

Show Tags

23 Dec 2013, 06:03

1

This post was BOOKMARKED

niyantg wrote:

Bunuel wrote:

morya003 wrote:

If S is the infinite sequence: S1=9, S2=99, S3=999, ..., SK = 10^K-1, ..., is every term in S divisible by the prime number p?

(1) p is greater than 2.

(2) At least one term in sequence S is divisible by p.

No, B is not correct. It's straight E: if p=3 then every term in S is divisible by p but if p=11 then some terms in S are divisible by p (for example 99 and 9999) and some are not (for example 9 and 999). Not sufficient.

Answer: E.

hope it's clear.

Hello Bunuel

I have a doubt here. Since we know after combining the 2 statements that the Prime number will NOT be 3 but any other Prime number that divides at least 1 number in the sequence. So now we know for SURE that EVERY TERM IS NOT Divisible by a particular Prime number( Which the Questions asks). 11 will also not divide all terms but few only.

SO should the Answer not be "C" ? Please correct me.

Thankyou

Actually question is asking , is every term in S divisible by the prime number p?

S1: p is greater than 2..Means wat? it means p cud b 3 ,5,7,11. If we say 3 then ans will be yes, Bt if we say 5 then we say no. Thats why Insufficient.

S2: at least one term is divisible by p. so ans wud b 3 or 11. 3 wud be divisible by every term of S, Bt 11 cud not be divisible by first term 9, and 999 etc.

Take both statement togather. still we cant give the ans, because p cud b 3 or 11.
_________________

Bole So Nehal.. Sat Siri Akal.. Waheguru ji help me to get 700+ score !

I'm happy to help if you wanna know about Ross & UMich, but please do not come to me with your GMAT issues or questions. And please add a bit of humor to your questions or you'll bore me to death.

Re: If S is the infinite sequence S1=9 S2=99 S3=999 SK=10^k-1 [#permalink]

Show Tags

16 Jan 2016, 00:55

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: If S is the infinite sequence S1=9 S2=99 S3=999 SK=10^k-1 [#permalink]

Show Tags

20 Feb 2016, 23:28

The only prime that divides all terms in the sequence: 9, 99, 999,.. is 3. So the question is essentially asking: is p=3? (1) p can be any prime number greater than 2, hence not sufficient. (2) p can be 3 or 11, hence not sufficient. Both taken together, again insufficient to identify p as 3.

Answer: E

boomtangboy summarizes aptly that the question tends to prey on the mistake that the test taker will consider 3 as the only possible value from statement (2).

Re: If S is the infinite sequence S1=9 S2=99 S3=999 SK=10^k-1 [#permalink]

Show Tags

16 Jul 2016, 00:23

1

This post received KUDOS

morya003 wrote:

If S is the infinite sequence: S1=9, S2=99, S3=999, ..., SK = 10^K-1, ..., is every term in S divisible by the prime number p?

(1) p is greater than 2.

(2) At least one term in sequence S is divisible by p.

From question stem we know S={9,99,999,9999,99999,999999...................99999999999999....} We can easily eye ball that this is divisible by either 3 or 11 or a combination of their multiples.

(1) p is greater than 2. Insufficient :- p can be 3 or 5 or 7 or 11 or 13 In some cases p divides ; in some cases it don't

(2) At least one term in sequence S is divisible by p. Insufficient again starting from the second term (99) all terms are divisible by either 3 and 11 But the first team 9 is divisible only by 3 and not by 11

So we cannot for sure whether the prime p that the question stem is referring to is 3 or 11.

BOTH STATEMENT INSUFFICIENT ANSWER IS E
_________________

Posting an answer without an explanation is "GOD COMPLEX". The world doesn't need any more gods. Please explain you answers properly. FINAL GOODBYE :- 17th SEPTEMBER 2016. .. 16 March 2017 - I am back but for all purposes please consider me semi-retired.

gmatclubot

Re: If S is the infinite sequence S1=9 S2=99 S3=999 SK=10^k-1
[#permalink]
16 Jul 2016, 00:23

There’s something in Pacific North West that you cannot find anywhere else. The atmosphere and scenic nature are next to none, with mountains on one side and ocean on...

This month I got selected by Stanford GSB to be included in “Best & Brightest, Class of 2017” by Poets & Quants. Besides feeling honored for being part of...

Joe Navarro is an ex FBI agent who was a founding member of the FBI’s Behavioural Analysis Program. He was a body language expert who he used his ability to successfully...