blsbball wrote:Is the positive integer n odd?
- (1) n = 2k + 1, where k is a positive integer
(2) 2n + 1 is an odd integer
Consider each option individually one at a time.
Objective: Is the positive integer n odd?
We need to find using the below given options' info whether we can determine n is odd or not?
Option 1: n = 2k + 1, where k is a positive integer
Put any +ve integer and check the value of n.
k = 1 then n = 3
k = 2 then n = 5
k = 9 then n = 19
Odd always. So sufficient. (If there would have single case where n = 2k+1 is no getting odd then the option would have been insufficient. But this is not the case here)
Option 2: Warning: forget Option 1. You must not bring any info from Option1.
2n + 1 is an odd integer
Try odd some values
2n+1 = 7 then n = 3 (Odd)
2n+1 = 9 then n = 4 (Even)
As we can have both possibilities (Odd/Even) for n this option is Insufficient.
Hence, A is the answer (as only option1 is sufficient)
If you are new to Data Sufficiency I would strongly recommend you to go through this:
https://www.beatthegmat.com/mba/gmat-dat ... ncy-videos
