I see this at least once a day on FB:
The vast majority of respondents say “16.” And I initially thought it was 16, too. I’m not a topologist, but having thought about it for a while, I now think the correct answer would be 15. Because I don’t think the big “hole” at the bottom of all one-piece shirts is a hole. I think it is the perimeter of a fabric that contains 15 holes. Or am I incorrect?
Can’t say — thousands of holes in the fabric weave. Can’t truly tell about the back of the shirt.
Heh, without being able to examine it further, it appears that there is a piece of cardboard inside the shirt. If that is the case, we don’t see any holes that could be in the back side of the shirt. I’d count the hole where you enter the shirt to be a hole, so I’d say 10.
IMO you are wrong with this bit. The armholes, neck hole, and waist hole are topologically equivalent. If the shirt was stretchy enough you could put your torso through the neck hole and have your head hanging out the waist hole.
Now there are implicit assumptions we’re making here. That the weave of the fabric doesn’t count as holes between each thread. That there aren’t hidden holes. That there’s no tag in the form of a strip of fabric folded in half and sewn down where the edges meet, nor a hanging loop at the back of the neck.
IMO the largest assumption we’re making is that this umpteen-generations plagiarized puzzle hasn’t been garbled into incorrectness somewhere along the way. Making the “right” answer wrong and rendering any explanation of that answer vacuous.
I’ve seen this as a trick before: among the many possibilities, there’s the possibility that there’s one enormous hole in the back of the shirt, not six separate ones. In addition, there’s the “does a straw have one hole or two?” question, which depends on how you define a hole. We just don’t have enough information to answer the question.
Yeah. Ultimately this isn’t a topological question; not at all. It’s a linguistic and misleading photography question.
As to @scabpicker’s cardboard insert, it certainly looks like that’s just the surface of the table showing through the holes. On closeup it’s the same grain, etc. In fact the entire background may be a single big piece of cardboard.
But yeah, you’re right to be suspicious that what looks obviously like [whatever] is in fact the trick, where the one thing it is not is “obvious”.
Yep. The puzzle answer is 16, but as with most of those stupid puzzles, there are no definitions.
Right.
How many holes does a bedsheet have? Or, to ask the same question in another way: is the edge a hole?
If we start from the position that this shirt, if fully intact, would have three holes (call any one of the waist, two sleeves, and neck the edge, and the other three are holes), then the answer could be any number ten or greater. Because it has those three, plus six more in the front, plus at least one more in the back. But it could be one big hole in the back, or six holes matching the six in the front, or any number of additional holes hidden by the front of the shirt.
A bedsheet has no holes. Because the edge is not a hole. And because a bedsheet, at least as an idealized topological entity is treated as a 2D surface.
But a t-shirt is not a 2-D surface. flat fabric has been joined to created an enclosed 3D volume. And that’s all the difference.
If I took a bedsheet and identified the head edge, then folded that over and sewed a couple inches of the left end of the head edge to the right couple inches of the head edge, I’d now have a 3D surface with one hole in it.
[Moderating]
Oh, and since this “puzzle” is mostly an exercise in reading the puzzle-poser’s mind, it’s better suited for IMHO. Moving.
Topologically, it is.
On further consideration, you are right and I was wrong. Time for more thinking on my part.
The ‘correct’ answer is irrelevant. The object of posting this is to have people stay on the page as long as possible, or better yet post an answer. It’s a manipulation of the algorithm.
But to answer the question, without any hidden information, the answer is 16.
It is not the number of dimensions, per se, that matters, topologically speaking, rather whether the space is or is not simply connected. More generally, its homology groups.
Sure, though, a spherical surface is simply-connected, and after you punch a hole in it it remains simply connected. (But there are clearly other features distinguishing the two cases, like higher homology groups.)
A Fair Witness would state that we don’t know if the shirt even has a back.
No, if you look at the collar, it definitely has at least some portion of a back – we just don’t know what it looks like. A better picture with higher resolution might allow us to see if the 6 big holes go through the back, too. Without more information, there’s no single answer, just a range of answers starting from 10 or 11 and extending to infinity.
ETA: The “99% fail” legend in the picture is just silly click-bait. There is no “correct” answer. For any putative right answer, one can always point to some possible fact not evident from the picture – but possible – that would make it wrong. The back of the shirt could have a zillion little holes in it; the bottom of the shirt could be sewn up and not be a hole at all, etc.
I say 12 – the obvious ones, front and back. Imagine going through old clothes to throw some out. I might sort all my shirts into two piles: those “with holes” and those “without holes.” A regular, undamaged shirt has zero holes; the neck and arm openings don’t count.
Here’s what I was getting at.
I think a regular ol’ shirt has three holes:
Now, if we assume there’s 12 additional holes in the shirt as shown in the OP (six on the front, six on the back):
then I would argue there’s 15 holes.
As I pointed out- the riddler claims the bottom is a hole- for the purposes of this riddle, 16 is the answer.
I do see your point- is the bottom part a “hole”?