After the psychic testing yesterday the conversation turned to the Friday Puzzle, and Suzanne Barbieri came up with this lovely classic…..

A man and his son are involved in a car crash. The father dies on the scene and the son is rushed to hospital. On arrival the surgeon on duty says “I can’t operate on this boy, he is my son!” How is this possible?

In fact, there are at least TWO perfectly logical solutions.

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



  1. I knew the answer partway into the first sentence, but the idea of two solutions threw me. I have a possible second solution, after a minute of thinking, through.

  2. I thought of two, but suspect there is a third and much more lateral answer. Shall think it over some more.

  3. Ack! This is my first time posting, and I didn’t read the instructions carefully. Please delete my 11:52 pm post.

  4. This is an oldie… My mother’s favorites to “test the kids” with were:

    “Why didn’t Moses bring mustard onto the ark?”

    “If a rooster lays an egg on the roof of a barn, which side will the egg roll down?”


    “Two trains are traveling down a track at 50 miles an hour. One left the town of Bingley at 2:05. The other left the town of Twangley at 2:04. In which town would the survivors be buried?”

  5. Are there any underlying assumptions we should know about? My problem is that I’m getting a lot more than two plausible solutions. (Current count is five.)

  6. I can think of three solutions, though based on my history here, I’m guessing only one fits the “rules”. Would like to know the other. Bet I disagree.

  7. The lion’s child has grown some more and taken over from his dear departed father’s footsteps. The lion’s child is standing behind the surgeon threatening to eat said surgeon should the operation go ahead.

  8. I’ve already heard the first answer (the “standard answer”). The second one was obvious, though it didn’t occur to me the first time I heard it (years ago.)

  9. Had to read it a few times. I got one solution. Can’t think of the other though. Hmmm.

  10. Immediate – we used to have a game called ‘Mindtrap’ full of questions like these (in fact I believe it included this classic) which I read through years ago and still hold them somewhere in my memory compartment labelled ‘generally useless information’….

  11. three milliseconds for the first answer and approximately another three for the next two solutions I have. FIVE solutions?! Woah, I’d like to know those!

  12. Heard this one before although can’t remember where.

    Not sure about how you could come up with 5 solutions unless you are really stretching the boundries.

  13. It’s not too hard to come up with a bunch of potential solutions if they only have to be consistent with the situation outlined in the puzzle. Which is why I’m wondering if there are unstated assumptions (i.e. boundaries) to the puzzle that I’m not aware of.

  14. This “puzzle” was in the Cosby Show about 25 years ago.

    I don’t think it works as well today as it may have back then.

  15. I’ve heard the “standard” answer before – but I can also think of two other solutions.

  16. A few seconds but I have heard it before. It is actually a little challenging, which is probably because of my upbringing. And, I only have one solution unless I am allowed to be playful.

  17. Michael Gray – That photo can’t lead you to false reasoning. It might lead you to make a conclusion that you then can’t find your way out of regarding the problem, but that’s not false reasoning. Then again, that picture might be of the actual surgeon in the problem. Different answer, same type of problem preventing people from getting there, though.

  18. Aha! Got it, well, one of the solutions anyway. Took me about 2 mins I think.

    I think it helped that I was given a sort of similar riddle a week ago about fathers and sons.


  19. Just listened to the skepticality interview and decided to come here and try the puzzle.

    it is a shame I had read this one before I got the first solution as soon as I read it when I read two solutions I got possibilities for a second. and typing this comment I got the possibilities of a 3rd/4th solutions.

  20. its the same as the two dogs riddle –
    “there are two dogs sitting next to each other a fat one and a thin one
    the thin one is the fat dog’s son
    but the fat dog is not the thin dog’s dad
    how is this possible??”

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