It’s the Friday Puzzle!


Today I am in Norway promoting Paranormality and giving a couple of lectures.  Details here. OK, to the puzzle….

To make French toast, I have to fry both sides of a slice of bread for 30 seconds. However, my frying pan can only hold two slices of bread at once. How quickly can I make three slices of French toast?

As ever, please do NOT post your answers, but do say if you think you have solved the puzzle and how long it took. Solution on Monday.

I have produced an ebook containing 101 of the previous Friday Puzzles! It is called PUZZLED and is available for theKindle (UK here and USA here) and on the iBookstore (UK here in the USAhere). You can try 101 of the puzzles for free here.


63 comments on “It’s the Friday Puzzle!

  1. M says:

    2 seconds to come up with an idea, 20 seconds to verify.

  2. Kyle Bown says:

    I think I got it. Took less than a minute (to solve).

  3. John Loony says:

    About 4 seconds.

  4. Robert says:

    Knew this one from earlier – but there’s a significant chance that one of the toasts won’t live up to your standards.

  5. mick says:

    got it in 20 sec.

  6. aanteladda says:

    Took my kid about half a minute though I had given him a minute and a half to do this .. Love this Q..

  7. Anonymous says:

    Took me 30s.

  8. Pete says:

    Phew a nice easy one this week. I had an answer by the time I had read to the end and it took only about a minute to prove to myself that the solution worked.

  9. Bob O'H says:

    Damn. I hate puzzles like this – it seems so simple, so I’m wondering what I’m getting wrong. I can even prove that I have the right answer and I’m worried.

  10. Drew says:

    Hopefully got this one right after about a minute of thinking

  11. Pierre says:

    At least with this one there shouldn’t be too much arguments 🙂

  12. Alex says:

    Hmm, different scenario but identical puzzle to the housework one from a couple of months ago..

  13. Jaq says:

    About 10 seconds. Quite surprised myself.

  14. Niva says:

    About 20 seconds. Easy one!

  15. Anders says:

    Depends on the frying pan. There is one answer for this:

    and one for a regular one-side-at-a-time pan

  16. Just a few seconds – maybe I woke up a bit quicker today. Time for some toast now

  17. Jenifer says:

    Got it. About 10 seconds.

  18. Paul Pearson says:

    I think I got it .. I think I got it. 3 seconds.

    But of course, there’s probably something I didn’t think of.

  19. Peter says:

    10 seconds.

  20. Sari1967 says:

    Think I have the answer but will have to wait till Monday for confirmation.

  21. Jerry says:

    Do I have to mow the lawn or feed the baby while I’m making the French Toast?

  22. Nice and easy. Two possible solutions. One requires logic, the other, some culinary knowledge. Both give the same answer.

  23. ChivNick says:

    An oldie, but a goldie.

  24. Damocles says:

    Ok … first I’ll need a frying pan … then some bread … oh hang on … I’ll just nip to the shops …

  25. Berhard says:

    easy, less than 10 secs

  26. rmb says:

    This reminded me of October 17, 2011 puzzle: three tasks and two persons.

  27. Martin says:

    Yes, just like a previous one.

    But, suppose the pan is circular and the pieces of bread are exactly square and two whole slices of bread fit into the pan…….

    Maybe there is a quicker solution….

  28. Marco says:

    Wow, that was easy…
    Had the idea almost instantly… took me about 30s to verify. But it is a nice happy feeling to be able to solve these puzzles 🙂

  29. Iain Shreeve says:

    I think I’ve got it, although do we need to factor in the eggs and quality of product?

  30. Lazy T says:

    easy solution, but French toast? ergh,,,,,I wouldn’t bother

  31. Tom Pedersen says:

    Got it, but the quality of the toast will suffer.

    Looking forward to “Kritisk masse” in Norway this weekend 🙂

  32. Todio says:

    Solved almost instantly. It had to mime the actions to confirm. Messy solution though.

    Did not factor in cinnamon or strip though.

    Mmmm, French Toast…

  33. Paul Durrant says:

    An easy solution to describe, rather harder to perform deftly.

  34. One Eyed Jack says:

    Not really a puzzler is it?

    You buy a clam grill big enough for 3 slices and do them all in 30 seconds. Simple. 😉

    Better yet, you buy a waffle iron and some nice blueberry waffles instead.

  35. Ariel says:

    I think it solved it, it tke me one and half minute to solve 🙂

  36. Matt says:

    It took me 1m 30s to work out the answer

  37. Chris says:

    does cooking the toast require a lawnmower, a vacuum, and someone feeding a baby?

  38. Duncan says:

    Isn’t this just a reworking of a previous puzzle? Anyway, got it! I recognised the problem immediately so it only took about 15s including pen and paper check.

  39. Anonymosity says:

    Got it before I finished reading the puzzle. 3 tasks that take a minute to perform, only two can be done at a time.

    Been there, done that.

  40. Zach says:

    About 15 seconds.

  41. Laith says:

    about 5 seconds to think of solution and another 25 to verify 😉 (30 sec)

    We’ve seen almost this same puzzle before here.

  42. theboywil says:

    As long as it’s purely the ‘cooking’ time of the toast we are calculating then the answer was immediate.

    However if ‘making’ the french toast involved buying, rearing or growing the ingredients (as well as combining them) then we don’t have enough data to be able to accurately answer the question.

  43. Mort Canard says:

    How many seconds does it take to shuffle one slice out of the frying pan and another one in?

    I would agree that one piece of French toast won’t be up to gourmet standards.

  44. Eddie (@edzeteito) says:

    All this talk of French toast is making me rather hugry.

  45. Eddie (@edzeteito) says:

    I’ve just spotted a smiley “:)” at the bottom of this web page. Do I get a/the prize??!! I think this is the secret purpose of the Friday puzzle – to see who spots it first.

  46. Adzcliff says:

    Eh?? Should I assume I haven’t got this? But surely…

  47. Easy, it takes an hour for you to go down to the shop and get another frying pan for the 3rd slice

  48. dismatic says:

    5 seconds for the first idea. 30 seconds to prove it to my family!

  49. RModule says:

    Well, probably 3-4 minutes. But unlike others here who used one nanosecond I had to convince myself that my upper bound also was a lower bound! The problem is not solved by merely presenting an algorithm which does the kitchen work faster than the naive approach – it also has to be the optimal one.

  50. RModule says:

    Oops. I should also add that I watched your appearance at Skavlan and that is why I googled your name and hence found this fine blog of yours. Too bad the other guests weren’t up for rationale.

  51. astjm says:

    Think I got it — took me about a minute (but that’s not the answer)

  52. spiderabc1 says:

    About 3 seconds for an answer. Then re-cosidered for about 3 minutes. Decided not to bother cutting any of the bread. Back to answer #1. Which i think is wrong.

  53. spiderabc1 says:

    I (sorry)

  54. Marion says:

    Well I have an answer, it seems to easy though so I may well have got it wrong. Just looked at my working out again though and think I have got it right as I haven’t fallen into the obvious trap!
    Yay Me!

  55. Anonymous says:

    i know the answer i heard be4 its less than 2mins more den 30sec

  56. Anonymous says:

    the clue is to take and put, take and put

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