It’s the Friday puzzle!


pizzaI had my favourite interview with a journalist yesterday. Half way through she asked, ‘So how long does it take to do the exercises in 59 Seconds’. Anway, I digress. Here is the second puzzle of the week…..

Update: OK, changed the one puzzle into two (thanks misterstewart)…

1) Two mothers and two daughters go out for lunch. They order a rectangular pizza and divide it into equal parts with five straight cuts. They then each had an equal share of the pizza. How is this possible?

2) Two mothers and two daughters go out for lunch. They order six slices of pizza and can share them equally between them. How is this possible?

The answer to this puzzle, and 100 others,Β  can be found in a new kindle ebook called PUZZLED, and is available in the UK here and USA here.


94 comments on “It’s the Friday puzzle!

  1. horuskol says:

    got it in about 15seconds this time…

  2. Victor Meldrew says:

    About 20 secs. Would be interested in participating in a podcast.

  3. Jetty says:

    Less than 5 seconds.

  4. Dave Sims says:

    Took me about 15 seconds as well πŸ˜› Not particularly hard mate!

  5. SillyBear7 says:

    I had the answer even before reading all of the question. I had a hunch and it turned out to be right.

  6. Jareth says:

    Took maybe fifteen seconds. I’m not positive it’s your solution, but it’s a perfectly valid one.

  7. lakritze says:

    Er … how is this not possible? Guess I got it …

  8. Sarah Lewis says:

    So easy. But I will still use this as reason to feel clever and smug for the rest of the day.

  9. Rob J says:

    I’m not sure the question is worded as tricksily as it might be intended to be. But yes, it’s pretty easy as it is worded. But as it is worded you could do it with pretty much any number of cuts, couldn’t you?

  10. I don’t get this puzzle. I can think of solutions, but they’re far too trivial to be satisfying. I don’t see what’s puzzling about the scenario described.

    As for the podcast, I’d definitely listen to the first one, and then more if I like it. Which is relatively likely, given that I’m interested in many of the things you write about, but I make no promises.

    Some of my personal preferences about podcasts: (a) I like podcasts that get to the point as opposed to the ones that sound like someone’s rambling dinner table conversation. (b) I like podcasts that discuss timeless topics which will be no less topical next year, as opposed to ones that discuss current events that no-one will remember in a week.

  11. Kelvin Kao says:

    I got it right away but I am sure there are other answers that also work.

  12. James M. says:

    I worked at Pizza Hut as a teenager, and I got this even before I finished reading the question, only because the answer is the exact way we used to slice up the “Sicilian Pan Pizza” if anyone remembers it. Keep up the good work Rich. “I’m a huge fan. No, really. I’m huge. I’m hung like a matured camel.” (sorry, borrowed that line from talk soup with john henson)

  13. ButMadNNW says:

    I have two possible answers, depending on how the cuts were made and what the familial relationships are. Probably over-thinking, but I can’t tell if I should take your verbiage at strict face value or not.

    And similarly to Flesh-eating Dragon (nice name!), I’d give the first podcast a go and see if I’m interested in continuing to listen. πŸ™‚ Love the poll options! They caused much laughing in this house.

  14. Unless I missed something, I’m puzzled how it’s a puzzle.

  15. Darragh says:

    Defo on the podcast, Richard. Sounds like it could be great.

    As for the puzzle – yep, got that, I think!

  16. Helveticat says:

    5 seconds unless I’m missing something; first thing I tried worked.

    RobJ – Yes I think you’re right, it can probably be done with n cuts, n > 1. I can see ways to do it with 2, 3, 4 and 5.

  17. I solved it immediately!

  18. Nick Sharratt says:

    Saw the ‘puzzle’ answer bit from reading first line as it’s a very common framework – but then got stuck for a few seconds because I skim read the rest and assumed the pizza was round. As soon as I checked the problem statement again the answer is trivial.

  19. Denny says:

    Haha, it’s all about linguistics!

  20. I think I’m missing something because it seemed too easy. I can think of a couple of ways of doing it.

    I tend not to listen to podcasts. I prefer videos because my hearing is slightly iffy and I like to see faces for speech.

  21. josephalford says:

    Took me a minute, because I was thinking it must be harder than that.

    As those folks above, don’t really get what the ‘puzzle’ is…unless it’s that you expect people to make equal shares straight away, then decide what to do with the remaining cuts, because that might stump someone for about 5 seconds!

    I’d definitely listen to a weekly (or whatever) podcast. Good stuff.

  22. eviesnowcat says:

    Got an answer in a minute or so but I wonder if I’ve cheated. I don’t think it’s as obvious as other posters seem to say.

    • ScreamingGreenConure says:

      Don’t worry, some people are so blindingly fast they got it years ago while still in the womb. You’re probably cool.

  23. Nikki says:

    GIMME PODCAST!!! There’s so much UK stuff I can’t get since I moved to Australia (i.e. anything on iPlayer or 4OD) and the TV here is awful. So please give me something nice to put in my ears. :o)

  24. TS says:

    No time, knew this from kindergarten.

  25. Bernard says:

    At last I got one in about 30 secs yippee, with the two solutions, but then again it might be as I lost mine at an early age and then only had sons only one of which likes pizza…

  26. Gert says:

    The second one I had pretty quick but was stumped on the first one until I realized it could be easily solved the same way as teh second.

  27. Rob says:

    Never mind the pizza,
    Is the podcast vote some kind of psychology test?
    The three options are very similar as to have the same meaning surely?

  28. Bagger says:

    Took me about 15 seconds to come up with a correct answer, but I don’t know if it’s the answer you are looking for πŸ˜‰

  29. Anders Elfgren says:

    I realized the ‘trick’ in the problem almost immediately so the second question was trivial. The first one took me a little bit longer because I missed that it was rectanguar – but I’m interested to see your definition of “equal”…. πŸ™‚

  30. Neil Jones says:

    Podcast? Hell yes. Your appearances on SGU are always enjoyable, so I’d definitely be interested in what you’d put into your own podcast… go for it.

  31. Michael K Gray says:

    1) You might be interested to learn that I had a very strong feeling of ‘DejΓ‘ Vu’ when reading this conundrum. (The 5 slices)
    Very strong.
    And as a result the solution that I imagined that I heard somewhere before came to me in a flash.

    2) The ‘6 slices’ puzzle seems so obvious and simple that I cannot determine why it is even classified as a dilemma…
    I am puzzled as to why it is a puzzle.

  32. ScreamingGreenConure says:

    Please name the poscast “Obey Richard Wiseman!”

  33. Icepick says:

    1) Yup. Second try.
    2) Immediately and I’m not that smart.

  34. AnnieJ says:

    Got it right away. The Friday puzzles are getting easier and easier!

  35. Mchl says:

    1) 30 seconds
    2)… I feel like something’s missing here…

  36. Dave says:

    1) More or less instantly
    2) Uh… Is this a trick question?

  37. ATravelller says:

    Solved the first one instantly (the picture really helped). Was stumped for a few seconds on the second one, but then I got it (I think). At that point, I realized that there were two possible solutions for the first puzzle.

    If I’m right about this, this will be the second puzzle I’ve solved, starting with the one from last ‘friday.’ They truly are getting easier πŸ˜›

    Also – never really listen to podcasts, sorry.

  38. Cosmin Romania says:

    1) I solved it in 1 min cuz I haven’t read it correctly the first time. πŸ˜›
    2) Solved it instantly.

  39. Mark Probst says:

    I would absolutely, definitely, religously listen to your podcast!

  40. BecomingEagle says:

    Not so easy to me, but I think I got it πŸ™‚
    The 1st is easier then the 2nd.

  41. Rob J says:

    OK. Now that the puzzle has been split into two, and with the prompting of some of the comments I see what it’s about, and now I have it.

  42. Seraph says:

    hmmm two mothers and two daughters

    I think it’s easy πŸ™‚

  43. Gus Snarp says:

    Took about 30 seconds. Tried a couple solutions and the fourth one worked, doesn’t seem particularly tricky. Don’t know if my solution to the second part is what you are going for, but it works.

  44. jscolley says:

    About 5 seconds

  45. PaoloV says:

    Far too easy – I didn’t even register the puzzle component this time it was so obvious.

  46. uksceptic says:

    Got the answer. Although embarresingly didn’t notice your blatent poll scam until after I had already clicked the top yes.

  47. Sagar says:

    Knew the answer before I finished reading the puzzle. I came across this puzzle a long time back. It would have been better if you left the puzzle with the first question and not updated with the second question.

  48. Stephen Hart says:

    oops. . .I’ve just realised that I miss read both puzzles completely – yes I feel like a berk. . .off to read them thoroughly this time. . .

  49. Travis says:

    Got the second one almost instantly. Took about 20 seconds to reason out the first one, which then gave me a second answer for the second one.

  50. Austin says:

    Less than a minute to get what I think is a correct answer, and that included double checking time. Also, would love a podcast. I’ve always enjoyed your appearances on other podcasts.

  51. Dan says:

    I ot the first one in a few seconds, and the second one I had a hunch about that turned out to be correct.

    Unless, of course, I’m missing some key wording or concept…

  52. Hilary says:

    Got both in about five seconds using the same reasoning. I’ve forgotten most of my algebra but I can still do fractions!

    I would certainly give your podcast a go, but much would depend on the content and the presentation. In my experience the quality of podcasts tends to be very variable.

  53. Sally says:

    I think that I have an answer to both. took a minute or so.

  54. John says:

    Great mental dexterity required for this solved in about 2 seconds, possibly 3

  55. amn says:

    Got it in about 10 seconds. Then, after, say, half an hour it occurred to me (subconsciously I think) that this puzzle has second solution.

  56. zygen says:

    The first one I got instantly, but the second took me about five minutes or so until I finally figured out where the trick could be.

  57. Alison says:

    About 2 seconds for part 2, slightly longer for part 1. Now I am just confused about the (supposed) difference between the two puzzles…

  58. rolak says:

    I think that pattern matching led me in a few seconds to the solution. If it is the right one…

  59. Vero! says:


    1. While I were drinking one “mate”
    2. while I were serving it again.

  60. Noadi says:

    Took me just a few seconds for part 2 and slightly longer for part 1 (I’m visual, needed to draw it).

    I would love a podcast.

  61. Cindy Hanson says:

    the puzzle, no time at all… reading everyones answer, more time than I care to admit… listen to podcasts… probably, most definately not.

  62. This is one of those “the mother was the surgeon” type riddles. I’m not that good at them, but I think I heard this one before.

  63. faye says:

    too easy!

  64. […] It’s the Friday puzzle! I had my favourite interview with a journalist yesterday. Half way through she asked, ‘So how long does it take […] […]

  65. slightly skeptical says:

    5 seconds on the first one, 2 minutes on the second one.

  66. Notatheist says:

    I’m calling ulterior motives again. The puzzle is too easy and the poll is sneaky. Something is rotten in Denmark.

  67. Wai says:

    got the second one after a bit of thinking… but still cracking my head on the first one…

  68. Michael K Gray says:

    BTW, There is more than one solution this/these puzzle(s).

    • ATraveller says:

      When I read that, I realized there was one more solution to both puzzles that I hadn’t considered- that makes 2/1 and 3/2. That last one is kinda tacky though IMO … So, lets bring the total puzzle solving time up to a minute and a half, which includes probably almost a minute of puffing myself up, feeling cock-sure that I had found all the answers and there couldn’t possibly be any more.

      I’m sure this time though … πŸ˜€

    • ATraveller says:

      Aaand we’ll make that 3/1 and 2/2, sorry πŸ™‚

    • Michael K Gray says:

      Yeah, I got the ‘kinda-tacky’ one too.
      Reminds me of the Ozarks…
      (Or Birmingham)

  69. Rebecca says:

    I got it pretty quickly, and have come up with several answers for part 1.

  70. bradyduga says:

    I got it in 59 seconds or less. Actually, a lot less this time.

  71. Rex says:

    I got it instantly, the first one was just very easy, and the second one is similar to another riddle I’ve heard.

    I like the poll. πŸ˜›

  72. Marco says:

    I think it took me 10 sec. but I only did part II.

    If I’m not mistaken there is more than one solution in two different ways.
    That is to say each solution to the part about the people involved (I can think of two solutions here) has then a number of solutions about the number of slices. Does that make sense?

    And another query, does the word “share” in English imply that they have to finish the pizza? Or is that being picky?


    • Alan says:

      Yes! Don’t waste good food! Think of the starving people in Africa. At least, that’s what my mother would say…

  73. Alan says:

    No time at all. i.e. the same amount of time I took to decide that I would definitely listen to your proposed podcast. Have loved your appearances on e.g. SGU

  74. MsMoll says:

    Hurrah! one I can do, about 5 seconds.

  75. Dan Mullen says:

    Got it straight away πŸ™‚

  76. Sebastian Hoch says:

    I got the first one in less than a minute.

    The second one took me about two minutes. I had to read it many times to figure it out.

  77. Laner says:

    For the extra-competitive of you; I got the answer 2 days before I read the question. Actually, I was born knowing the answer. Actually, I tell a lie, I had the answer before I was even conceived!

  78. Lucia says:

    Easy… Meanwhile i read it i know… But now i want pizza!

  79. Royal says:

    My dream retirement would involve a awesome log cabin in the mountains. Who needs a beach?

  80. Kareem says:

    Awfully enlightening many many thanks, It appears to be like like your current readers may possibly possibly want even more blog posts similar to this continue the wonderful effort.

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