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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.

Is there something that I'm misunderstanding? Please advise.
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Re: The infinite sequence a{1}, a{2}, …, a{n}, … is such that a{ [#permalink]
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Aurele wrote:
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.

Is there something that I'm misunderstanding? Please advise.


Please read here: the-infinite-sequence-a-1-a-2-a-n-is-such-that-a-156741.html#p1250455

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.
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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.
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Re: The infinite sequence a{1}, a{2}, , a{n}, is such that a{ [#permalink]
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Re: The infinite sequence a{1}, a{2}, , a{n}, is such that a{ [#permalink]
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