Veritas Prep GMAT Instructor
Joined: 01 May 2019
Posts: 50
Re: M23-22
[#permalink]
20 Jun 2019, 13:47
A quick way to test whether or not order matters is to try making the same selection in two different orders to see if you get a new result.
For example, if I am making a 3-person group from A, B, C, D, and E and I select A, then B, then C, I get the same group as when I select C, then B, then A. Same result = order doesn't matter = combination.
On the other hand, if I am selecting 1st, 2nd, and 3rd place from A, B, C, D, and E, and I select A, then B, then C, I get a different order than when I select C, then B, then A. Different result = order does matter = permutation.
Trying that here, if I am picking 2 numbers from {1,2,3,4,5}, and I pick 1, then 2, I get the same sum (3) as when I pick 2, then 1. Same result = order doesn't matter = combination.
While there are a few key words that indicate whether or not order matters, we don't always get them, so the best way to figure it out is to test it yourself.