It’s the Friday Puzzle…..

69

A nice simple one this week.  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.

From a full deck of 52 playing cards, how many cards do you need to draw to ensure that you have four of a kind in your hand?

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.

69 comments on “It’s the Friday Puzzle…..

  1. kroketje says:

    seams easy, 20 sec.

    • Dave's Neighbour says:

      0.238921961696395381535549104701266481251516152361839 seconds. If you are seriosuly lucky then the first 4 cards drawn could meet the desired criteria. On the other hand,if you are unlucky and the first 39 cards drawn are either say hearts, diamonds or spades, then you need to draw a 40th card

    • Dave Cross says:

      @Dave’s Neighbour: did you miss the bit where Richard said “As ever, please do NOT post your answers”?

    • Dave's Neighbour says:

      I think Dave’s Cross

    • -M- says:

      Richard Wiseman: is it possible to ban certain people by IP address?

    • Internet Outrage Counselor says:

      Probably not, but it IS possible for you to NOT read the comments until you worked out your answer thereby eliminating the ‘spoiler’ effect.

    • Glen says:

      Dave’s Neighbor, he’s one for you. “Do not look directly at the sun for 10 seconds”

    • Dave's neighbor says:

      Eh?

    • Gus Snarp says:

      Of course it’s possible to ban people by IP adress, blogs do it all the time. Does Dave’s Neighbor do this often? It’s rather rude when one has been expressly asked not to post the answer.

  2. stuart hamilton says:

    40 seconds

  3. Mick says:

    got it, also 20 sec.

  4. Roland says:

    Depends. If it’s a random draw it’s another number than when I can pick my own cards ;-)

  5. Nafisa says:

    30 seconds

  6. Captain Wow says:

    Are the cards face up or face down?

  7. Julie says:

    Unless there is a twist – I think I’ve got it.

  8. laconicsax says:

    Is this assuming an honest shuffle, break, and deal?

    • One Eyed Jack says:

      It doesn’t matter if the deck is shuffled or comes as-is from the manufacturer. The answer will still be the same.

  9. Mad Kev says:

    Yes,40 seconds.

  10. Anonymous says:

    I didn’t count how long it took me. Under a minute though. You’re right, it wasn’t too tough!

  11. Eddie says:

    So easy this one. If I’m wrong, shoot me.

  12. Martha says:

    Four of a kind what?

  13. vmos says:

    Four of the same suit or number?

  14. Julie says:

    “A fair question”, David, but when are Richard’s questions ever fair?

  15. Chris says:

    I took it to mean four of the same suit…

  16. High Janus says:

    If the deck is face up then the asnwer is 4

  17. edwardv says:

    So simple I could post the answer and no one would care.

    • One Eyed Jack says:

      It won’t be obvious to everyone. There is a wrong answer that a good number of people will jump to first.

  18. Lazy T says:

    It would take me ages to draw them like that bloke did a few days ago

  19. Stan says:

    Also about 20 sec. It’s interesting that quite a few folks took about 20 sec.

    • The other Matt says:

      Wait for monday….,its not so a “nice simple one”, i think. Or did you know suddenly what means “four of a kind” ?

  20. Cheryl Kohl says:

    Took me 21 seconds. Clearly I’m stupid

  21. Anonymous says:

    I agree with Dave’s Neighbor. The worst case scenario is that you have to wait for the 40th card to ensure 100% success

    • Mervulon says:

      Do you agree that it’s okay to specifically ignore the instructions regarding posting your answer prematurely? Do you simply not care, or are you cognitively defective, or are you just such a firebrand rebel you can’t help your anti-authoritarian impulses? You and Dave’s Neighbor should start a bad-ass street gang. You could travel town-to-town on souped-up Segways, breaking hearts, scoffing at the law, tearing off mattress tags, and tagging spoilers on Movie Marquis posters with indelible marking pens.

    • Anon says:

      I think he just likes winding you up Mervulon.
      You have to admit – he is pretty good at it.

    • Photon Boy says:

      The best way to piss off an attention seeker is to ignore them. Sorry Mervulon, but after your post, I think that Dave/Dave’s neighbour/Anonymous will be back for more on Monday.

    • Mervulon says:

      That’s okay… just so long as they’re not rolling through my ‘hood on those Segways… we sure don’t need that kind of trouble….

  22. David D says:

    “…. to ensure …” To absolutely guarentee?

  23. Kristian says:

    Fell into the trap at first, but realised it and figured out the solution! About a minute.

  24. Roger says:

    10 seconds, and I should have left it at that.
    There’s no point in reading the Friday comments

  25. frwits says:

    it took me 25 secs (if my swatch is working properly).

  26. Dharmaruci says:

    four cards of the same deck require me to draw ___ cards. why is that blank so diffikult for some people?

    now if multiple decks are sorted together that would be harder

    • Martha says:

      Why? If it were two packs, the answer would be twice as many, wouldn’t it?

    • The Masked Twit says:

      No Martha
      No matter how many packs there are the answer is the same
      PS Unless we are we playing to Lemmy’s
      rules when the answer would be four more

    • dharmaruci says:

      yes m. le twit that does seem to be the case.
      a more interesting puzz to me is “how many cards you would have to draw and perhaps discard to guarenty you have four different cards (eg not of same type)”

    • One Eyed Jack says:

      Actually, with two decks, the answer remains the same. The limiting factor is still how may cards you can draw without making 4 of a kind. Adding another deck doesn’t change that.

    • Attention seeking Segway Driver (in da' hood) says:

      Dharmaruci
      The answer to your question is the same as that for Richard’s question – different cards though.

  27. Phil H says:

    It took less time than it would have done to find four of a kind in a pack

  28. Christine says:

    The answer we got in half a minute well my incredibly brilliant son got it before I had a chance to finish reading it lol

  29. Steve B says:

    Less than a minute.

  30. Mike Torr says:

    A few seconds.

  31. Yep, just a few seconds. When the puzzle is this easy, I’m sure I’ve gone wrong somewhere.

  32. JohnLoony says:

    I can draw cards until doomsday, but none of them will ever mysteriously materialise in my hand, as if by magic, no matter how long I carry on drawing. I fear that I would run out of pencils first. I think it’s a trick question.

  33. Mike Hayward says:

    I’m not sure if my answer is correct but it took me 32.4 seconds to arrive at it. My thought process was that I always had a one-in-four chance of drawing the same suit of card in a deal (of four cards). I extrapolated this out until I was certtain of having three of a kind in three deals. The last deal might get me the forth four-of-a-kind card on the first card dealt, the second, or the third, but I figured that there would be no doubt that I would have four of a kind by the fourth card. My head hurt by this time, so I had to go lie down.

  34. deepfield says:

    This is not a puzzle, but just a question…

  35. Damon says:

    I see people here make jokes about how easy this puzzle is, but I remember spending a significant amount of time at university doing pigeon hole principle (the basis of this puzzle), and people not getting it and asking many many questions on it during revision sessions. I always found it incredibly easy but apparently it is worthy of being varsity level…

  36. beaky says:

    ~20 seconds, easy answer, but:
    It depends on what you mean by “ensure”; I take it to mean “be certain”.
    Are the cards in fact face-down?
    Four of WHAT kind? The kind with that particular pattern on the back?

    THEN I read some of the comments. Gee, folks, this is becoming just another collection of ad hominem ripostes. Boring.

  37. Philosopher's stoned says:

    Obviously too straightforward a question for attention seeking pedantics to benefit from. However, as for attention seeking trolls…….

  38. Holden Caulfield says:

    Is it Monday yet?

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