I found the following problem that says: If I have 5 cats and I want to take a picture of them in groups of three cats in a row, in how many ways can I put the cats for taking their picture?
It is a simple problem, but I have a question if this is a permutation or combination problem. For example, if for me the order matters (for example if I want to put the cats ordered by weight) I can put any of the 5 cats in the first position, then any of the remaining 4 in the second position and any of the remaining 3 in the last position giving me:
$5*4*3=60$ possible ways to arrange the cats.
However, if for me is irrelevant the order then I could use the formula of combination without repetition giving me: $C(5,3)=10$ possible ways to put the cats on a row.
Which one would be the correct answer? Sorry for the simple question, but I get confused in determining in which case apply one formula or the other.
Thanks