Answer to the Friday Puzzle….

27

On Friday I posted this puzzle….

I have just placed some money into one of three boxes: a gold box, a silver box and a lead box.  Each box has an inscription.  At least one of the inscriptions is true and at least one of them is false.  The inscriptions are:

Gold box: The money is not in the silver box.

Silver box: The money is not in this box.

Lead box: The money is in this box.

You can only open one box, and if you open the box containing the money you get to keep the cash.  Which box should you open?

If you have not tried to solve it, have a go now.  For everyone else, the answer is after the break.

You should open the gold box.  If the money were in the silver box, all the inscriptions would be false.  If it were in the lead box, all of the inscriptions would be true.

Did you solve it?

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

27 comments on “Answer to the Friday Puzzle….

  1. Michael Bray says:

    Pick the GOLD box (that’s where the money is). The Gold box statement is true. The silver box statement is also true. The lead box statement is false. Thus, the requirement that at least one statement is true and one statement is false is satisfied.

    If the money was in the silver box then all three statements would be false, and if the money was in the lead box then all three statements would be true.

  2. dharmaruci says:

    very clever mr wiseman. but please anwser me this. if there were no money at all the statements would be TRUE, FALSE. TRUE. how can i even know if there is money in any of the boxes? this is important if it takes me much effort (ie a chainsaw) to open a box or if the no money boxes conatin a bobby trap.

    • Eddie says:

      Thumbs down to this comment.

    • Mervulon says:

      But there is money in a box – it is a stipulation of the puzzle. So the answer to you query is – “dumb question.”

    • Damocles says:

      dharmaruci, What if reality is an illusion?

    • dharmaruci says:

      to help you with your perceptions, Mervulon, the puzzle does not tell us the cost of opening the boxes. there may be a nasty surprise also in the gold box. we may be better off taking only just the empty silver box and so keeping the silver.

      think of it as if the question was “i have put some money in one of a tiger, a cornflake packet, or a handgrenade.” logic tells us to open the cornflakes even if other logic tells us the money is in the tiger. unless it is a lot of money of course, lol.

    • dharmaruci: When you sit down to play a game of chess, you are agreeing to follow the rules. To knock over the board and scream “Take that, Bobby Fischer! Where’s your chess game now?” would be childish. The rules for solving a puzzle include the assumption that the person setting the puzzle is telling the truth. So there is money in one of the boxes.

      I have been very explicit here, but somehow I doubt you will appreciate it. So, in a few words: If you can’t solve the puzzle, admit it and express your appreciation. Or say nothing.

    • Turd says:

      Dharmaruci is a Jack in a Box!

    • Eddie says:

      Damocles, what is reality if not an illusion?

    • Wigan FC says:

      @aharmlessdrudge

      “If you can’t solve the puzzle, admit it and express your appreciation. Or say nothing.”

      Dharmaruci is allowed to say whatever he pleases, whether he solves the puzzle or not. Since when has it become your job to tell others what they can or can’t say? I for one enjoy reading Dharmaruci’s posts and those of many others. Just because someone has a different point of view to you does not make their contribution any less worthwhile, and Dharmaruci always makes for interesting reading.

  3. John says:

    I solved this very quickly on Friday in under a minute and then spent half an hour wondering whether it was unwise to assume that Richard was telling the truth.

  4. Michael Bray says:

    dharmaruci: I think when the post says “I have just placed some money into one of three boxes”, that means that there is some money in one of the three boxes.

  5. Ian says:

    Thanks for that, Richard, it’s a clever one and, yep, got it right :) Hope the weekend went well and brought more ideas and food for thought. Thanks again for the weekend brain workout :)

  6. Tom says:

    Eh? “If it were in the lead box, all of the inscriptions would be true”

    The lead inscription says “Lead box: The money is in this box.”

    Why wouldn’t I open the lead box?

    • One Eyed Jack says:

      Read the problem again. At least one of the statements must be true, and at least one of the statements must be false. If the money is in the lead box, all three statements are true; so that can’t be where the money is.

  7. Chris says:

    Is the first box solid gold? If so, stuff the money – I’m having the box.

  8. Lazy T says:

    I took them all to the airport and sent them through security scans, I was arrested for traces of illegal substances. What had you been doing with the boxes before using them in the puzzle?

  9. Jenifer says:

    Yay, I got it right. :D

    • Laith says:

      Me too! I hardly ever get these, the ever end up being a bit complex in a domain I don’t quite get or I miss something really obvious. That was my fear about this one.

  10. The other Matt says:

    Didnt got it… But i would take the Gold box itself, if its a golden box !

  11. I like this kind of puzzle. Figured it out quickly, yet it was a bit of a challenge. Keep them coming, Richard, and don’t listen to the requests of those nerdy math guys.

  12. El Duderino says:

    I can barely contain my indifference

  13. Hugh Janus says:

    Yawn

  14. Alix Royer says:

    I got it, but that’s no big thrill (it took me, a 53-year old university graduate, about 35 seconds). The thrill, however, is that my nephew and his best friend, both 10 years old, got it in 5 seconds…! Made me feel ……

  15. Deja says:

    Gold box

  16. Sito De Web says:

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