# 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:** 11\ **Page:** 6
**Author:** ![Count\_Blucher](https://avatars.discourse-cdn.com/v4/letter/c/c5a1d2/32.png) [@Count\_Blucher](https://boards.straightdope.com/u/Count_Blucher)\ **Post date:** [May 31, 2017, 2:29am UTC](https://boards.straightdope.com/t/pizza-question-which-answer-is-right/787700/101 "2017-05-31T02:29:10Z")
50 posts and no one asked “deep-dish, thin crust, massive extra cheese, or ‘That Horrific 80s Style Dominoes’…?” ---
**Author:** ![Derleth](https://avatars.discourse-cdn.com/v4/letter/d/b9e5f3/32.png) [@Derleth](https://boards.straightdope.com/u/Derleth)\ **Post date:** [May 31, 2017, 4:43am UTC](https://boards.straightdope.com/t/pizza-question-which-answer-is-right/787700/102 "2017-05-31T04:43:29Z")
Teacher should always take good care of testees, whether they’re their own or testees they’re handling for someone else. Tweaking them is liable to make them sensitive, and leading them down a false path can be very hurtful indeed. There are few things worse than testees with their lines crossed, and they shouldn’t get the dirty end of the stick, either. Maybe we should get bagel dogs, instead. ---
**Author:** ![Colophon](https://avatars.discourse-cdn.com/v4/letter/c/f05b48/32.png) [@Colophon](https://boards.straightdope.com/u/Colophon)\ **Post date:** [May 31, 2017, 11:13am UTC](https://boards.straightdope.com/t/pizza-question-which-answer-is-right/787700/103 "2017-05-31T11:13:26Z")
I would propose this simple test for the teacher: Bill Gates gives 4/6 of his wealth to person A. The homeless guy on the corner gives 5/6 of his wealth to person B. Obviously the teacher will choose to be person B and get more cash, right? I’ll be person A. ---
**Author:** ![Defensive\_Indifference](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/defensive_indifference/32/6502_2.png) [@Defensive\_Indifference](https://boards.straightdope.com/u/Defensive_Indifference)\ **Post date:** [May 31, 2017, 11:52am UTC](https://boards.straightdope.com/t/pizza-question-which-answer-is-right/787700/104 "2017-05-31T11:52:43Z")
> [@Biotop](#): > > Is it only me, or does this whole pizza school question story seem improbable to anyone else? I also regard this story with some skepticism. First, the source is Some Guy on Reddit, so right off the bat I think there’s about a 5/6 probability that the story is bullshit. Also, the picture shows only one question and part of the next, so we don’t get the context. It may be the case that this is one question in a series based on a set of givens we can’t see. There could have been instructions like, “For questions 5-9, assume Marty and Luis each buy an 8” personal pizza…" Who knows? It may be that the teacher wrote a stupid question and graded it poorly, or it may be that this is yet another example of some asshole trolling with a fake or misleading story about "the American educational system ". Because it’s easier to point to some dumb thing that happened (or didn’t) in some backwater school as the reason for whatever educational problems we have instead of dealing with systemic inequality and political stupidity. ---
**Author:** ![RTFirefly](https://avatars.discourse-cdn.com/v4/letter/r/c77e96/32.png) [@RTFirefly](https://boards.straightdope.com/u/RTFirefly)\ **Post date:** [May 31, 2017, 8:17pm UTC](https://boards.straightdope.com/t/pizza-question-which-answer-is-right/787700/105 "2017-05-31T20:17:32Z")
> [@glee](#): > > I’ve been a teacher for 27 years and have designed successful exam questions. > I agree with all the above posters - the student answered the question correctly (and cleverly) whilst the teacher was wrong on several counts: > > - shouldn’t have designed the question that way if if the idea was to simply to test if students knew that 4/6 was less than 5/6 > - shouldn’t have included the phrase ‘Marty ate more pizza than Luis’ as a statement of fact if it was a lie > - should have congratulated the student for an excellent answer Going another step or two, let’s break this down: The problem states three facts: 1. Marty ate 4/6 of his pizza. 2. Luis ate 5/6 of his pizza. 3. Marty ate more than Luis. “How is that possible?” in any reasonable world is asking, “how can we resolve this seeming contradiction?” The student comes up with the obvious way: Marty had a bigger pizza. Another way, as some have already suggested, is that along with eating 4/6 of his own pizza, Marty had \>1/6 of someone else’s pizza. Now the teacher tosses in a new assumption: (4) the pizzas are all the same size. But Marty still could have eaten a chunk of someone else’s pizza. OK, let’s add: (5) Marty just eats from that one pizza. Now we have five facts that can’t all be true. But here’s the deal: we don’t know which ‘fact’ is false, and _neither does the teacher._ If we can toss out fact #3, why not fact #1 or fact #2 instead? Maybe Luis only ate half his pizza. Maybe Marty ate all of his. If the pizzas are the same size, and Marty only ate from his pizza, we \*still \*can’t say Marty ate less pizza than Luis. > [@Thudlow\_Boink](#): > > I propose that the teacher be given an 80% pay cut, immediately followed by a 90% raise. She should be perfectly happy with that, since 90% is greater than 80%. 😃 ---
**Author:** ![Balance](https://avatars.discourse-cdn.com/v4/letter/b/ccd318/32.png) [@Balance](https://boards.straightdope.com/u/Balance)\ **Post date:** [June 1, 2017, 1:23am UTC](https://boards.straightdope.com/t/pizza-question-which-answer-is-right/787700/106 "2017-06-01T01:23:21Z")
> [@ekedolphin](#): > > I side with the student, but I’m confused: What answer was the teacher going for? The “I mindlessly plug numbers into word problems without thinking about them” answer, I would surmise. ---
**Author:** ![Chessic\_Sense](https://avatars.discourse-cdn.com/v4/letter/c/7c8e57/32.png) [@Chessic\_Sense](https://boards.straightdope.com/u/Chessic_Sense)\ **Post date:** [June 1, 2017, 3:03am UTC](https://boards.straightdope.com/t/pizza-question-which-answer-is-right/787700/107 "2017-06-01T03:03:15Z")
> [@The\_Other\_Waldo\_Pepper](#): > > “…and the surgeon said, _‘I can’t operate on this boy; he’s my son!’_ Explain.” > “Uh, is it that the surgeon was that boy’s mother?” > “What? No, that can’t be right.” Funniest thing I’ve read all year. Seriously. > [@Nars\_Glinley](#): > > 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) I don’t want to bump an ancient thread, but that question is not unreasonable if you know that ‘round one up and one down by similar amounts’ is an estimation technique. They rounded a number up by 1/8 and the other down by 1/10. The up/down feature is an important part of it, and one that’s easy to miss. In your post, and in lots like these, there’s a hidden but standard technique that’s not obvious unless you’re in class all week. In the OP’s case, it’s just stupid. Not only is the teacher wrong, but he’s demonstrably wrong. The student demonstrated why, so no further discussion is necessary. “It’s not possible” can be and has been disproven, so what’s left to argue about? ---
**Author:** ![Riemann](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/riemann/32/3133_2.png) [@Riemann](https://boards.straightdope.com/u/Riemann)\ **Post date:** [June 1, 2017, 3:14am UTC](https://boards.straightdope.com/t/pizza-question-which-answer-is-right/787700/108 "2017-06-01T03:14:18Z")
> [@Chessic\_Sense](#): > > …I don’t want to bump an ancient thread, but that question is not unreasonable if you know that ‘round one up and one down by similar amounts’ is an estimation technique. They rounded a number up by 1/8 and the other down by 1/10. The up/down feature is an important part of it, and one that’s easy to miss… Huh? Not when you’re _subtracting_ one number from another one. ---
**Author:** ![Johanna](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johanna/32/8318_2.png) [@Johanna](https://boards.straightdope.com/u/Johanna)\ **Post date:** [June 1, 2017, 5:52am UTC](https://boards.straightdope.com/t/pizza-question-which-answer-is-right/787700/109 "2017-06-01T05:52:31Z")
> [@Derleth](#): > > Teacher should always take good care of testees, whether they’re their own or testees they’re handling for someone else. Tweaking them is liable to make them sensitive There’s material for a fine off-color joke in that… ---
**Author:** ![Gus\_Gusterson](https://avatars.discourse-cdn.com/v4/letter/g/85f322/32.png) [@Gus\_Gusterson](https://boards.straightdope.com/u/Gus_Gusterson)\ **Post date:** [June 1, 2017, 1:22pm UTC](https://boards.straightdope.com/t/pizza-question-which-answer-is-right/787700/110 "2017-06-01T13:22:13Z")
Our daughter had a science test this week. She got a 95. The question she got wrong showed a chart of a bus’s speed, with speed on the Y axis and time on the X axis. There were 5 line segments on the chart. Segment E-F went from X=10, Y=5 to X=15, Y=5 (that is, from time 10 to time 15, the bus’s speed was 5). The question: What was the bus doing in segment E-F? (A) The bus was accelerating (B) The bus was stationary © The bus was decelerating (D) The bus was moving at a constant speed She chose D. The teacher said the answer is B. She tried to discuss it with him but he just said “The speed didn’t change so the bus was stationary.” She believes that he thought that the Y axis was distance, not speed, since other charts on the test were configured that way. She pointed that out and he still insisted that she was wrong. She pointed out a different line segment where the speed was constant at zero for 4 units of time to show how a stationary bus would look on the chart but he still didn’t get it. So she gave up. I guess we should have posted it on Facebook. ---
**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:** [June 1, 2017, 2:06pm UTC](https://boards.straightdope.com/t/pizza-question-which-answer-is-right/787700/111 "2017-06-01T14:06:01Z")
> [@Chessic\_Sense](#): > > I don’t want to bump an ancient thread, but that question is not unreasonable if you know that ‘round one up and one down by similar amounts’ is an estimation technique. They rounded a number up by 1/8 and the other down by 1/10. The up/down feature is an important part of it, and one that’s easy to miss. I understood the assignment and I highly value estimation. However, I believe any problem that uses subtraction of two positive numbers and results in a greater number is fundamentally flawed and defeats the purpose of the exercise. [Previous page](https://boards.straightdope.com/t/pizza-question-which-answer-is-right/787700.md?page=5)