# Pizza question: which answer is right? **URL:** \ **Category:** In My Humble Opinion\ **Created:** [May 30, 2017, 3:50am UTC](https://boards.straightdope.com/t/pizza-question-which-answer-is-right/787700 "2017-05-30T03:50:10Z")\ **Posts on this page:** 20\ **Page:** 5
**Author:** ![pulykamell](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pulykamell/32/3166_2.png) [@pulykamell](https://boards.straightdope.com/u/pulykamell)\ **Post date:** [May 30, 2017, 7:43pm UTC](https://boards.straightdope.com/t/pizza-question-which-answer-is-right/787700/81 "2017-05-30T19:43:21Z")
> [@Procrustus](#): > > When the teacher asks “how is this possible?” the student is tasked with trying to think outside the box and come up with a possible solution. The student did that by stating one pizza was bigger. So, yes, we need “assumptions,” but this question was apparently designed to get students to question their assumptions. Too bad the teacher didn’t understand that. Exactly. That seems the entire point of the question, to me. I can’t remember having tests that would lie to me when asking something like “how is this possible?” expecting an answer of “it’s not.” Perhaps “is this possible?” but not “how is this possible” which is extremely leading and suggests it is possible (and, in this case, it clearly and obviously is). I think the teacher is flat-out wrong. That said, I also take with a huge grain of salt these click-baity/viral posts of “real world” tests with a controversial correction by the teacher. I’m inclined to believe that this one has a reasonable chance of being true, but I have a little bit of skepticism. ---
**Author:** ![OldGuy](https://avatars.discourse-cdn.com/v4/letter/o/3bc359/32.png) [@OldGuy](https://boards.straightdope.com/u/OldGuy)\ **Post date:** [May 30, 2017, 8:10pm UTC](https://boards.straightdope.com/t/pizza-question-which-answer-is-right/787700/82 "2017-05-30T20:10:45Z")
Reminds of the time in ninth grade, the teacher wrote on the board: “Defend the proposition: The problem with being open-minded is that your brains may fall out.” About one-third of the class tried to write reasoned arguments about situations in which being too open-minded might be a bad thing. When the teacher handed the assignments back he criticized us for spending so much of our time on the obvious incorrect conclusion. Our counter that the instructions were “Defend” not “Discuss” fell on deaf ears. ---
**Author:** ![Rysto](https://avatars.discourse-cdn.com/v4/letter/r/ecccb3/32.png) [@Rysto](https://boards.straightdope.com/u/Rysto)\ **Post date:** [May 30, 2017, 8:25pm UTC](https://boards.straightdope.com/t/pizza-question-which-answer-is-right/787700/83 "2017-05-30T20:25:35Z")
> [@OldGuy](#): > > Our counter that the instructions were “Defend” not “Discuss” fell on deaf ears. In a just world, that teacher would one day hire a defense attorney who decides to follow the teacher’s logic. :smack: ---
**Author:** ![Little\_Nemo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/little_nemo/32/3120_2.png) [@Little\_Nemo](https://boards.straightdope.com/u/Little_Nemo)\ **Post date:** [May 30, 2017, 8:31pm UTC](https://boards.straightdope.com/t/pizza-question-which-answer-is-right/787700/84 "2017-05-30T20:31:51Z")
> [@Thudlow\_Boink](#): > > That doesn’t answer my question. I wasn’t asking why you should have some basic assumptions, but why “the pizzas are equivalent” should be one of them. That ball’s not in my court. Most people are saying the student’s answer is the only correct answer and the teacher’s answer is wrong. I said the student’s answer is correct from some points of view and the teacher’s answer is correct from other points of view. So I don’t need to disprove the student’s answer. All I need to do is show how the teacher’s answer can possibly be right. ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [May 30, 2017, 8:35pm UTC](https://boards.straightdope.com/t/pizza-question-which-answer-is-right/787700/85 "2017-05-30T20:35:07Z")
The simplest defense for the student is the question “How is this possible?”. He provided an answer to that question, the teacher did not. ---
**Author:** ![Czarcasm](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/czarcasm/32/4050_2.png) [@Czarcasm](https://boards.straightdope.com/u/Czarcasm)\ **Post date:** [May 30, 2017, 8:48pm UTC](https://boards.straightdope.com/t/pizza-question-which-answer-is-right/787700/86 "2017-05-30T20:48:12Z")
My question to the teacher after this happened would be, “Are there any other questions on this test that contain outright lies?” ---
**Author:** ![Hari\_Seldon](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hari_seldon/32/5173_2.png) [@Hari\_Seldon](https://boards.straightdope.com/u/Hari_Seldon)\ **Post date:** [May 30, 2017, 8:52pm UTC](https://boards.straightdope.com/t/pizza-question-which-answer-is-right/787700/87 "2017-05-30T20:52:54Z")
My opinion is that the teacher’s answer is stupid and wrong. When a question is asked, the student is entitled to assume that it has an answer and the student answered in what was really the only way possible. By saying that the question is unreasonable indicts the teacher for asked such a stupid question. ---
**Author:** ![BigT](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bigt/32/12044_2.png) [@BigT](https://boards.straightdope.com/u/BigT)\ **Post date:** [May 30, 2017, 8:55pm UTC](https://boards.straightdope.com/t/pizza-question-which-answer-is-right/787700/88 "2017-05-30T20:55:26Z")
> [@Little\_Nemo](#): > > That ball’s not in my court. Most people are saying the student’s answer is the only correct answer and the teacher’s answer is wrong. I said the student’s answer is correct from some points of view and the teacher’s answer is correct from other points of view. So I don’t need to disprove the student’s answer. All I need to do is show how the teacher’s answer can possibly be right. Not a single person is asking you to disprove the student’s answer. They’re asking you to back up your answer from the teacher’s point of view. You are asserting that there is a reasonable interpretation that the student should assume the pizzas are the same size. You have to back that up. You don’t just get to make up arbitrary rules to defend someone as possibly being right. And you still have to explain how the statement “How is this possible?” can accept the answer “it is not possible.” ---
**Author:** ![Czarcasm](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/czarcasm/32/4050_2.png) [@Czarcasm](https://boards.straightdope.com/u/Czarcasm)\ **Post date:** [May 30, 2017, 9:00pm UTC](https://boards.straightdope.com/t/pizza-question-which-answer-is-right/787700/89 "2017-05-30T21:00:00Z")
The problem contained this statement of fact: “_Marty ate more pizza than Luis._”. ---
**Author:** ![Kamino\_Neko](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kamino_neko/32/34_2.png) [@Kamino\_Neko](https://boards.straightdope.com/u/Kamino_Neko)\ **Post date:** [May 30, 2017, 9:09pm UTC](https://boards.straightdope.com/t/pizza-question-which-answer-is-right/787700/90 "2017-05-30T21:09:51Z")
> [@Little\_Nemo](#): > > Because if you don’t accept some basic assumptions then any answer is possible. Right. And there are two basic assumptions that you and the teacher are discarding. 1. The question isn’t flat out lying. 2. The question is saying what it means to say. You and the teacher require one or both of these to be wrong. ---
**Author:** ![Czarcasm](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/czarcasm/32/4050_2.png) [@Czarcasm](https://boards.straightdope.com/u/Czarcasm)\ **Post date:** [May 30, 2017, 9:24pm UTC](https://boards.straightdope.com/t/pizza-question-which-answer-is-right/787700/91 "2017-05-30T21:24:03Z")
> [@Kamino\_Neko](#): > > Right. And there are two basic assumptions that you and the teacher are discarding. > > 1. The question isn’t flat out lying. > 2. The question is saying what it means to say. > > You and the teacher require one or both of these to be wrong. I just pointed out that the question is flat-out lying. ---
**Author:** ![Weisshund](https://avatars.discourse-cdn.com/v4/letter/w/ba8739/32.png) [@Weisshund](https://boards.straightdope.com/u/Weisshund)\ **Post date:** [May 30, 2017, 9:48pm UTC](https://boards.straightdope.com/t/pizza-question-which-answer-is-right/787700/92 "2017-05-30T21:48:22Z")
Student is correct 4/6ths of LARGE is more in volume than 5/6ths of SMALL :smack: ---
**Author:** ![BeepKillBeep](https://avatars.discourse-cdn.com/v4/letter/b/9e8a1a/32.png) [@BeepKillBeep](https://boards.straightdope.com/u/BeepKillBeep)\ **Post date:** [May 30, 2017, 10:54pm UTC](https://boards.straightdope.com/t/pizza-question-which-answer-is-right/787700/93 "2017-05-30T22:54:51Z")
> [@Procrustus](#): > > When the teacher asks “how is this possible?” the student is tasked with trying to think outside the box and come up with a possible solution. The student did that by stating one pizza was bigger. So, yes, we need “assumptions,” but this question was apparently designed to get students to question their assumptions. Too bad the teacher didn’t understand that. Exactly. I like to think I’m an intelligent person and I guarantee that if presented with that question my assumption would be that they are looking for something clever. to explain how that state could be correct despite the apparent error. Something exactly like what the student provided. Ultimately, I’d say it is clear what the teacher (or test writer) intended the question to ask, but they butchered the phrasing and because of that the student’s answer is correct. The teacher’s answer is absolutely wrong because there is a way for it to be possible. ---
**Author:** ![erysichthon](https://avatars.discourse-cdn.com/v4/letter/e/d07c76/32.png) [@erysichthon](https://boards.straightdope.com/u/erysichthon)\ **Post date:** [May 30, 2017, 11:06pm UTC](https://boards.straightdope.com/t/pizza-question-which-answer-is-right/787700/94 "2017-05-30T23:06:31Z")
> [@Biotop](#): > > Is it only me, or does this whole pizza school question story seem improbable to anyone else? Yeah, that photo is pegging the needle on my bullshit detector. In my entire time in the American public education system, I never got a trick question like this in math class. And I sure as hell never had a teacher provide a neatly-written explanation of why an answer was wrong. If it was wrong, all I got was an X (in red ink, not green). I think it’s fake. ---
**Author:** ![Nars\_Glinley](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/nars_glinley/32/8177_2.png) [@Nars\_Glinley](https://boards.straightdope.com/u/Nars_Glinley)\ **Post date:** [May 30, 2017, 11:42pm UTC](https://boards.straightdope.com/t/pizza-question-which-answer-is-right/787700/95 "2017-05-30T23:42:03Z")
> [@erysichthon](#): > > Yeah, that photo is pegging the needle on my bullshit detector. > > In my entire time in the American public education system, I never got a trick question like this in math class. And I sure as hell never had a teacher provide a neatly-written explanation of why an answer was wrong. If it was wrong, all I got was an X (in red ink, not green). > > I think it’s fake. That is certainly a possibility. The explanation makes it even more likely to be fake since the same answer was probably given by most students. I can, however, guarandamntee you that this happened in my daughter’s 7th grade math class. [http://boards.straightdope.com/sdmb/showpost.php?p=4302557&postcount=1](http://boards.straightdope.com/sdmb/showpost.php?p=4302557&postcount=1) ---
**Author:** ![TokyoBayer](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tokyobayer/32/13989_2.png) [@TokyoBayer](https://boards.straightdope.com/u/TokyoBayer)\ **Post date:** [May 30, 2017, 11:49pm UTC](https://boards.straightdope.com/t/pizza-question-which-answer-is-right/787700/96 "2017-05-30T23:49:17Z")
> [@Drunky\_Smurf](#): > > The teacher is a retard and needs to be fired. As does the idiot who hired the teacher. Yes, let’s fire everyone who ever makes a single mistake. Burn their house and salt their fields as well. > [@Little\_Nemo](#): > > [Frog riddle: does the answer make sense?](http://boards.straightdope.com/sdmb/showthread.php?t=787806) In that thread, the [Boy or Girl](https://en.wikipedia.org/wiki/Boy_or_Girl_paradox) problem is linked to. From there: > [@](#): > > Gardner initially gave the answers 1/2 and 1/3, respectively, but later acknowledged that the second question was ambiguous.[3] Its answer could be 1/2, depending on how you found out that one child was a boy. The ambiguity, depending on the exact wording and possible assumptions, was confirmed by Bar-Hillel and Falk,[4] and Nickerson. The mathematician is acknowledging something you refuse to: that poorly worded questions can change the answer. > [@guizot](#): > > Or perhaps this: _ **Martiy ate 4/6 of a pizza and Luis ate 5/6 of a pizza. Marty says, “I ate more than you.” Is his statement reasonable?** _ This is really the answer. The problem with the test question is that the basic assumption is that you don’t question the test for false information. The phrasing for guizot’s question directly addresses reasonableness. If the student provided the answer that the pizza was larger, there would be a better case for marking it wrong as a smart ass. ---
**Author:** ![UDS](https://avatars.discourse-cdn.com/v4/letter/u/ecae2f/32.png) [@UDS](https://boards.straightdope.com/u/UDS)\ **Post date:** [May 31, 2017, 1:16am UTC](https://boards.straightdope.com/t/pizza-question-which-answer-is-right/787700/97 "2017-05-31T01:16:37Z")
> [@Little\_Nemo](#): > > Because if you don’t accept some basic assumptions then any answer is possible. > > For example, why assume that these are the only two pizzas Luis and Marty have ever eaten? The question doesn’t say that. Maybe in the course of his lifetime Luis has eaten five thousand pizzas and Marty’s only eaten five hundred. So Luis ate more pizza than Marty and the student’s answer was wrong. > > When you start allowing any possible assumptions into the question, no mathematical problem is solvable. On that view, the student’s answer is correct. The student made no assumptions; he deduced from the facts given that the pizzas were of unequal size. The teacher, by contrast, assumed a fact not given, and indeed a fact inconsistent with the facts given - viz, that the pizzas were of equal size. ---
**Author:** ![Weisshund](https://avatars.discourse-cdn.com/v4/letter/w/ba8739/32.png) [@Weisshund](https://boards.straightdope.com/u/Weisshund)\ **Post date:** [May 31, 2017, 1:31am UTC](https://boards.straightdope.com/t/pizza-question-which-answer-is-right/787700/98 "2017-05-31T01:31:52Z")
> [@Little\_Nemo](#): > > There’s the principle that when you hear hoofbeats, you should assume it’s a horse not a zebra. Why assume the pizzas were different sizes if you weren’t told that? Unless one is in africa, then perhaps horse, perhaps zebra, perhaps wildebeest When one is in a pizza parlor all manner and sizes of pizza exist. ---
**Author:** ![The\_Other\_Waldo\_Pepper](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/the_other_waldo_pepper/32/12370_2.png) [@The\_Other\_Waldo\_Pepper](https://boards.straightdope.com/u/The_Other_Waldo_Pepper)\ **Post date:** [May 31, 2017, 1:56am UTC](https://boards.straightdope.com/t/pizza-question-which-answer-is-right/787700/99 "2017-05-31T01:56:33Z")
> [@TokyoBayer](#): > > The problem with the test question is that the basic assumption is that you don’t question the test for false information. Heh. If you did, how would it help? “Yeah, it says he ate 5/6 of a pizza – but maybe that’s false, and it was only 1/6.” The student’s answer can work even if we for some reason figure a lie is in the mix. But it _also_ works even if all of the given info is true, is the thing. ---
**Author:** ![Kamino\_Neko](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kamino_neko/32/34_2.png) [@Kamino\_Neko](https://boards.straightdope.com/u/Kamino_Neko)\ **Post date:** [May 31, 2017, 1:56am UTC](https://boards.straightdope.com/t/pizza-question-which-answer-is-right/787700/100 "2017-05-31T01:56:45Z")
> [@Czarcasm](#): > > I just pointed out that the question is flat-out lying. I was writing my post when you posted. Had the thread open for a while. [Previous page](https://boards.straightdope.com/t/pizza-question-which-answer-is-right/787700.md?page=4) [Next page](https://boards.straightdope.com/t/pizza-question-which-answer-is-right/787700.md?page=6)