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# Is the positive integer n odd?

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Intern
Joined: 13 Sep 2017
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Is the positive integer n odd?  [#permalink]

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Updated on: 17 Sep 2017, 19:56
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00:00

Difficulty:

35% (medium)

Question Stats:

84% (00:52) correct 16% (01:09) wrong based on 88 sessions

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Is the positive integer n odd?

(1) n= 2k+1, where K is positive integer
(2) 2n+1 is an odd integer

Originally posted by Jennifervn on 17 Sep 2017, 19:00.
Last edited by chetan2u on 17 Sep 2017, 19:56, edited 1 time in total.
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Re: Is the positive integer n odd?  [#permalink]

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17 Sep 2017, 19:19
(1) 2k + 1 -> n odd. Sufficient.
(2) 2n + 1 odd -> n even -> not odd. Sufficient.

I think the answer should be D.
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Re: Is the positive integer n odd?  [#permalink]

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17 Sep 2017, 19:40
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1
Jennifervn wrote:
Is the positive integer n odd?
(1) n= 2k+1, where K is positive integer
(2) 2n+1 is an odd integer

I wonder why the answer is B instead of D? Thanks a lot!

Hi Jennifervn , are you sure the OA is B?

Question : Is n odd?

Statement 1
- $$n=2k+1$$. $$2k$$, whatever value of k, will always be EVEN. $$even+1$$-->$$even+odd=odd$$
- Therefore Statement 1 is sufficient.

Statement 2
- $$2n+1=ODD$$.
- I don't think this give definite answer for n.
- If n=1 (odd) --> $$2+1=3$$, ODD.
- If n=2(even) --> $$4+1=5$$ also ODD
- Because whatever n value, 2n always even. An even+1 always ODD.
- So statement 2 is not sufficient.

Wdyt?
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Re: Is the positive integer n odd?  [#permalink]

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17 Sep 2017, 19:43
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The answer will be A only

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Re: Is the positive integer n odd?  [#permalink]

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17 Sep 2017, 19:50
From statement 1 "n" is always odd irrespective of the value of K (Positive integer)

From Statement 2 "n" can be even or it can be odd.

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Re: Is the positive integer n odd?  [#permalink]

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17 Sep 2017, 19:54
1
Jennifervn wrote:
Is the positive integer n odd?
(1) n= 2k+1, where K is positive integer
(2) 2n+1 is an odd integer

I wonder why the answer is B instead of D? Thanks a lot!

Hi..

Pl follow rules before posting a Q.
You will have to relook into the source, if the answer is anything other than A.

n is a positive integer..

Let's see the statements..
1) n=2k+1, k is Positive integer
So 2k will always be EVEN and 2k+1 will be ODD..
Thus n is ODD
Sufficient
2) 2n+1 is an odd integer..
This means 2n is even..
But n can be anything..
n=1,2n+1=2+1=3....ans YES
n=2, 2n+1=4+1=5...ans NO
Insufficient

A
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Joined: 13 Sep 2017
Posts: 8
Re: Is the positive integer n odd?  [#permalink]

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17 Sep 2017, 19:59
chetan2u wrote:
Jennifervn wrote:
Is the positive integer n odd?
(1) n= 2k+1, where K is positive integer
(2) 2n+1 is an odd integer

I wonder why the answer is B instead of D? Thanks a lot!

Hi..

Pl follow rules before posting a Q.
You will have to relook into the source, if the answer is anything other than A.

n is a positive integer..

Let's see the statements..
1) n=2k+1, k is Positive integer
So 2k will always be EVEN and 2k+1 will be ODD..
Thus n is ODD
Sufficient
2) 2n+1 is an odd integer..
This means 2n is even..
But n can be anything..
n=1,2n+1=2+1=3....ans YES
n=2, 2n+1=4+1=5...ans NO
Insufficient

A

Thanks a lot for your explanation. I've just joined the club and this is the first time i have one post. My wonder is that whether i did something wrong to follow the rule of the website. Please kindly just let me know. Thanks again!!
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Joined: 12 Oct 2017
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Re: Is the positive integer n odd?  [#permalink]

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29 Nov 2017, 18:42
(1) n= 2k+1, where K is positive integer => n is always odd. => sufficient
(2) 2n+1 is an odd integer => 2n is even => n can be odd or even => insufficient.
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Posts: 2
Re: Is the positive integer n odd?  [#permalink]

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29 Nov 2017, 19:28
Sstaement 1 alone is sufficient

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Re: Is the positive integer n odd? &nbs [#permalink] 29 Nov 2017, 19:28
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