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OK, to the Friday puzzle….

I don’t like to boast, but I wear a clean shirt every day.  I drop off my week’s laundry, and pick up the previous week’s load, every Tuesday night.  What is the minimum number of shirts I need to keep me going?

As ever, please do NOT post your answers, but feel free to say if you solved it and how long it took.  Answer on Monday.



  1. Erm, either that was blindingly easy, I’ve been doing too much programming lately, or I’ve got it horribly wrong.

    About 10 secs to solve, about 5 mins second-guessing myself 😉

  2. I have two possible answers depending on something that I won’t comment on for fear of giving it away. I suspect I know what the “real” answer is, though.

    1. I wonder if we have the same two answers…

      Either of which would be correct depending on whether an intentional misdirect was used, or whether questionable grammar/phrasing is being used….

  3. I think I know what the twist is supposed to be. Not very impressed with it, though.

    On last week’s Friday Puzzle, I posted a comment reminding readers of the puzzle I sent Richard last August, and asking for opinions on whether I should stop waiting for it to appear as a Friday Puzzle and run it on my own blog instead.

    I think I will do that. Not this week (which is the height of the Adelaide Fringe Festival and therefore exciting enough already), but soon. Maybe I’ll post the puzzle on Monday March 21 and the solution/analysis on Monday March 28, or something like that. Keep an eye on these comment threads (both the questions and answers ones) and I’ll let you know.

    1. I even thought one of the recent ones was yours (Richard made secrete of its provenience) but in the end, was not. If you have only one puzzle, consider to warn the post at least with one week of anticipation… at least for me, I don’t come here the number of times I used to be.

    2. At the moment, Monday March 21 or Tuesday March 22 seems most likely (i.e. within 24 hours of when Richard posts the solution to the 3rd puzzle for March). Plans can change (say, if I’m busier than I expect to be), but if they do I can’t guarantee being able to tell people in advance.

      I will try to give reasonable notification, but if you (generic) want to make absolutely sure of not missing it, you could always contact me and ask me to tell you when it’s up. There’s an email address on my blog that’s not hard to find.

  4. Quick instinctive answer fairly instantly, then five minutes attempting to work it out. It’s like feeling you know something but you can’t quite put your finger on it.

    Now pondering how to adjust the given problem to reduce the number of shirts.

  5. I suppose it’s a coincidence that Richard is now tweeting about *vests*?! ;D

    Instinctive answer in about 10 seconds, correct answer in about 3 mins…

  6. I think I got the solution two… It was obvious from the beginning, but doesn’t dispense some time for checking

  7. I think I’m missing something here – no, I KNOW I am, I can only come up with the obvious answer to this one. Can’t be right, too simple. Totally stuck for the first time on these.

    1. Try numbering the shirts, and writing out exactly which ones he wears, drops off and picks up for a few weeks. See if the obvious one really does work.

    2. ? yes, Steev, it does. And if the amount is different after ‘a few weeks’, you still have to have the obvious amount the first two weeks to get you started. I can’t find another answer.

    3. So which shirt should Richard wear to take his dirty laundry in and take the new pile away? That’s where I finally got the obvious one not quite working.

    4. It doesn’t matter, since he has no expectation of getting it done right away – “… and pick up the previous week’s load.”

  8. It took about a minute but the correct answer flashed in my mind. See, I wash my shirt myself and daily and I have two of them.

    1. Is there any need to be so rude?

      If you don’t like it, [expletive deleted] to another free blog, and leave this one to the people who find these puzzles enlightening.

      This one is beautifully simply phrased, but does require more than just the initial first thought.

  9. Got this one and have checked my answer. After confusing myself with shirts and days realised I had actually got it right. (I think!)

  10. Ah, I spotted one very slight little catch that changed my answer from the absolute blindingly obvious. If you would like a reasonably oblique hint then paste the following into http://www.rot13.com and click the “Cypher” button:

    Ur qbrfa’g jnfu uvf fuvegf ng ubzr.

  11. I’ve got an answer I’m quite certain about, based on the stated resource consumption rate and the cycle time (ha!). One of these might be considered non-obvious, but otherwise the numbers are hard, no tricks, if’s and buts.

  12. I made a guess in a few seconds, less than minute. Then I spent about 5 minutes working it out on paper to confirm my guess.

    1. Thinking about it some more I do have an ‘out-of-the-box’ solution that cuts 1 off the number you need.

  13. That cannot be so easy…
    Whats about if the Tuesday is a bank holiday ? The Laundry will be closed !
    How often you buy a new shirt ?
    Does you bring the shirts by yourself or does it anybody for you ?

  14. Its asked for the MINIMUM. So i got a solution ! But you have to spend one hour half naked in the launderette…

  15. Hmmm got one answer in about one minute had to do pen and paper to make sure I got it right….. or so I hope….I mean I could decrease the number but it would only work for a guy and a slow laundry or I should say a laundry with few customers….

  16. I think anyone who has ever done serious programming will think they get it in seconds, then wonder if it was supposed to be that easy, and then see the hook in a few more. Anyway, about 20-30 seconds for what I’m certain is the right answer.


  17. i am a student from china who are interested at this blog .i wonder if there have another world invisible ,not only this one?

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