1:10 AM
I found the above links either using Approach0 or via Google. — Martin Sleziak 4 mins ago
Now the question is whether we have more copies of the same question which I did not find.
And another question is, which of them can be closed as duplicates and which one should be chosen as duplicate target.

1 hour later…
2:40 AM
It seems that Workaholic does a lot of searching for duplicates using Approach0, see here or here.

1 hour later…
3:43 AM
@MartinSleziak I have noticed quite curious fact that there were some posts which contained both type of links, like here. I have stumbled upon a few such posts when editing.

9 hours later…
12:18 PM
As far as I can say these two questions are duplicates.
The newer question was for some time on the HNQ list, so it already has two answer (the older one has only one) and about the same number of views.
I have edited the title to be mor clear than the original title "How to enumerate this linear algebra problem?" But I still did not use MathJax (so that it stays in the HNQ.)
If it stays in HNQ list, it might attract some more attention and nice answers.
So I guess that a reasonable thing to do with those two questions is either close in the direction older $\to$ newere or merge, right?
Although I see that somebody has already cast the first vote in the direction newer $\to$ older.
So let's wait what other users think and how will they vote in the close votes review queue.
I am not sure whether this is a factor, but the older question would be a reasonable candidate for missing context closure.
The question is a duplicate of the linked one from 5 days ago (search the site - at least the recent ones). I used that as a duplicate target, because it has an answer. However, I upvoted your question. At least you thought about the matter (unlike the other asker). You also found the correct answer! — Jyrki Lahtonen ♦ Dec 18 '15 at 6:05
Let's hope we will not end up again with several questions closed as duplicates of a question which is closed as off-topic (missing context).