Last visit was: 16 Sep 2024, 14:43 It is currently 16 Sep 2024, 14:43
Toolkit
GMAT Club Daily Prep
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

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.

# The infinite sequence a{1}, a{2}, …, a{n}, … is such that a{

SORT BY:
Tags:
Show Tags
Hide Tags
Intern
Joined: 03 Dec 2012
Status:Yes. It was I who let the dogs out.
Posts: 36
Own Kudos [?]: 335 [5]
Given Kudos: 27
H: B
GMAT Date: 08-31-2013
Math Expert
Joined: 02 Sep 2009
Posts: 95555
Own Kudos [?]: 659297 [3]
Given Kudos: 87276
Math Expert
Joined: 02 Sep 2009
Posts: 95555
Own Kudos [?]: 659297 [1]
Given Kudos: 87276
Intern
Joined: 24 Oct 2013
Posts: 4
Own Kudos [?]: [0]
Given Kudos: 5
Re: The infinite sequence a{1}, a{2}, …, a{n}, … is such that a{ [#permalink]
Hey,

I don't get how the OA can be A. Can anyone please explain?

As per my understanding the OA should be E:

Statement 1 says "n is a multiple of 3."

By applying the formula given in the question stem, we can find that a5=15 and that a7=21. Yet, 15 divided by 7 gives a remainder of 1, while 21 divided by 7 gives a remainder of 0. Hence, IMO statement 1 is insufficient.

Statement 2 says "n is an even number".

Also insufficient: a2=8 gives a remainder of 1, while a4=14 gives a remainder of 0.

Statements 1 and 2 combined say "n is a multiple of 3 and n is an even number".

IMO insufficient. For instance, a9=24 and a14=36. Both are multiples of 3 and are even. However, the former result gives a remainder of 3 whereas the latter one gives a remainder of 1.

Math Expert
Joined: 02 Sep 2009
Posts: 95555
Own Kudos [?]: 659297 [0]
Given Kudos: 87276
Re: The infinite sequence a{1}, a{2}, …, a{n}, … is such that a{ [#permalink]
Aurele
Hey,

I don't get how the OA can be A. Can anyone please explain?

As per my understanding the OA should be E:

Statement 1 says "n is a multiple of 3."

By applying the formula given in the question stem, we can find that a5=15 and that a7=21. Yet, 15 divided by 7 gives a remainder of 1, while 21 divided by 7 gives a remainder of 0. Hence, IMO statement 1 is insufficient.

Statement 2 says "n is an even number".

Also insufficient: a2=8 gives a remainder of 1, while a4=14 gives a remainder of 0.

Statements 1 and 2 combined say "n is a multiple of 3 and n is an even number".

IMO insufficient. For instance, a9=24 and a14=36. Both are multiples of 3 and are even. However, the former result gives a remainder of 3 whereas the latter one gives a remainder of 1.

We need to find the remainder when when $$a_{n}$$ is divided by 7. (1) says n is a multiple of 3. Why are you checking the remainder when $$a_5$$ or $$a_7$$ is divided by 7. Is 5 or 7 a multiple of 3?

Hope it helps.
Intern
Joined: 24 Oct 2013
Posts: 4
Own Kudos [?]: [0]
Given Kudos: 5
Re: The infinite sequence a{1}, a{2}, …, a{n}, … is such that a{ [#permalink]
Thanks a lot for the explanation. Don't know why I confused both.
Non-Human User
Joined: 09 Sep 2013
Posts: 34876
Own Kudos [?]: 880 [0]
Given Kudos: 0
Re: The infinite sequence a{1}, a{2}, , a{n}, is such that a{ [#permalink]
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: The infinite sequence a{1}, a{2}, , a{n}, is such that a{ [#permalink]
Moderator:
Math Expert
95555 posts