Answer to the Friday Puzzle…

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Over the weekend The Observer carried the first article about Rip It Up. It reveals what the book is all about – Forget positive thinking. It’s time for positive action. You can read the article here.

So, on Friday I set this puzzle…..

A man is stranded on an island covered in woodland and surrounded by cliffs. One day disaster strikes and a fire starts on the west end of the island. The wind is blowing from the west and soon the whole island will be burned, killing everything in its path. The man cannot put out the fire, so how does he survive it?

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

He takes a piece of wood and lights it on the fire. He then returns to a point a few metres in from the east end of the island and starts a fire there. This new fire will burn across right to the east coast and the man can take shelter in the area it burns out. Simple as that!

Did you solve it? Any other solutions?

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.

43 comments on “Answer to the Friday Puzzle…

  1. Roland says:

    Assuming that the fire spreads slower than the man can walk, and the new fire burns out fast enough, before the original fire reaches him. But luckily Richard lives in an ideal world where this always happens ;-)

    • ladymac says:

      I AGREE, BUT MORE THAN YOUR SALIENT POINTS SIR-FIND IT ILLOGICAL AND CHEATING-sorry for lg. print, didn’t notice till done my husband selfishly left on caps as he often does-guess I’m tired of checking & just type.

  2. I thought it was a grammar trick: “The whole island will be burned, killing everything in its path”. There’s nothing here about the path of the fire, only that of the island. I guess continental drift is involved.
    :-)

  3. Clint says:

    Not difficult. Backburning is a procedure commonly used to fight bushfires, spoken about on news stories all the time.

    • Kristian says:

      As a Dane, we don’t have a whole lot of bushfires going on… I didn’t think of this at all. It’s quite clever – if all things go right of course. My only other answers were silly ones relying on the shape of the island, an inland lake, or my ability to climb the cliffs.

    • One Eyed Jack says:

      That’s not what back burning is.

      “Back burning” is lighting a fire that burns back into the original fire. In this solution, the fire burns in the same direction as the original. The hero of our story then takes shelter in the newly burned area.

      I see your smugness and trump it with my pedantry.

    • Anonymous says:

      One-eyed Jack wins on sheer, unadulterated pedantry!

    • fluffymike says:

      perhaps ‘controlled burning’ is more accurate than back-burning

  4. That’s the solution that occurred to me, though it does make a number of assumptions; that you have time to cross the island, ahead of the blaze, start the fire, in the just the right place, so that it burns out and is cool enough that you can shelter there by the time the main fire gets across the island… And how long are you going to survive after the fire, anyway?

  5. I had a different solution. As he’s surrounded by mountains he had to climb them to get to the middle, so why not clinb out. Or, my other thoughts was that if he couldn’t climb them, he isn’t in danger as he’s still on the shore, outside the ring of mountains, and not threatened by the fire.

  6. Interesting. I was thinking, just jump into the water, float around a bit (perhaps on the raft you were building to get off the island anyway) and get on the island again when it’s safe, most likely on the west side.

    • Navneeth says:

      Jumping off the island was my idea too.

      By the way, I don’t understand Richard’s answer.

  7. David D says:

    If the cliffs are unclimbable how did he get up there in the first place? Therefore I thought he would be down on the beach and thus the fire above would not affect him.

  8. Dave Bull says:

    And how close do you have to get to such a fire to light your splint – surely he’d be crispy in no time?

  9. -M- says:

    Answer was spoiled last friday. Did not get it myself.

    • -M- says:

      What may also help is to dig a hole and take shelter below the ground. It does not even have to be very deep. I’ve once seen on television that that works.

  10. kaggyxaggy says:

    I came up with the same solution as -M- dig a hole and hide below.

  11. Bobby says:

    My solution was that he was west of the fire when it started. Since half of this island can be called the west and the question states that the fire starts in the west and spreads east there’s an awful lot of potential safe areas for him to be. He could be at the western most point of the island and the fire could start just west of centre.

    That’s my take anyway. X

  12. Steve Jones says:

    Of course he saved himself in the short term, but is now condemned to a slow, lingering death as his only source of sustenance, the fruits of the forest, is now gone.

    My advice is end it quickly, and jump off the cliff…

  13. Lazy T says:

    He should just turn the island round.

  14. Bletherskite says:

    I did think of the backburning but my other solution was that the cliffs went down around the edges rather than up (I don’t think it specifies in the question), therefore he could go to the edge of the island, climb part-way down the cliffs and then climb back up to the top once the fire had burned out.

  15. Furie says:

    With a strong wind coming from the west, surely the new fire will just take him out quicker and not spread as fast as the original?

    I say make him climb halfway down the cliffs and hang on for dear life. He has a better chance of survival.

  16. Bence says:

    Got the solution, but I think it’s also plausible if we assume that he was the one who started the fire to signal for help (from an enviromental point of view it’s still a disaster).

  17. Mike Torr says:

    Wow, I totally misunderstood this one! I took “How does he survive” to mean “How DID he survive”, and then just assumed that he was the one who started the fire accidentally, so he’s still safe at the Western end of the island…

  18. Katrina says:

    I’m from Australia. There are lots of bushfires here. Backburning is common and something the indigenous people did/do. This was easy. Heard this riddle often as a kid!

  19. SofARMaths says:

    I just made the island have an inlet on the West wth the fire starting on the opposite bank and moving to the East. Need to draw it!

  20. Doesn’t “surrounded by cliffs” mean that the cliffs are around the outside edge of the island? The woodland area is inside. How did he get to the woodland area? Did he fall out of a hot air balloon? I see him as outside the cliffs and thereby having to do nothing. The puzzle doesn’t say he’s in the woodland area..

    Questions about Richard’s solution: The fire is probably moving as fast as the wind is blowing. How fast can this dude run? Will the piece of wood remain lit as he runs with it in all that wind? Isn’t it going to take quite a while for that newly set fire to die down and be cool enough to step on even if he’s wearing combat boots (unlikely as that may be)?

    Does the word “farfetched” come to mind or am I just lacking imagination?

  21. Mickey D says:

    I assumed it was the man who started the fire in the first place, so he was already safe behind the fire on the westside of the island…

  22. One Eyed Jack says:

    Look around you– can you construct some sort of rudimentary lathe? ….

  23. duckdog says:

    If the island is “woodland” and not just “grassland”, I suspect the heat from a forest fire would be so intense he wouldn’t be able to just walk up and light a branch. Just saying….

  24. One Eyed Jack says:

    Lord of the Flies solution…

    The smoke from the fire is noticed by a passing ship, which changes course and rescues our hero before he dies.

  25. Anonymous says:

    The word “soon” in the question invalidates Richard’s solution …

  26. Dig a deep whole and wait it out underground. Many burrowing mammals survive fires this way, I understand. :)

  27. Mind you, you’d probably suffocate….ah, worth a shot!

  28. JohnLoony says:

    Clever! Completely different from all the half-baked ideas I had. But it depends on having the right combination of (a) how fast the man can run (b) how fast the fire spreads (c) how fast the ground cools after being burnt out.

  29. JohnLoony says:

    The best feeble idea I had on Friday was that the wording which says “The man cannot put out the fire, so how does he survive it?” allowed for the possibility that he survives the fire by means of dying another way, i.e. jumping off the cliff.

  30. Calgacus says:

    My thoughts were that he can’t survive. If the fire doesn’t get him, starvation would!

  31. Henry Ruddle says:

    It seemed obvious to me that since he was on the island already but it had cliffs that were apparently too sheer to climb (otherwise why mention them if not to take away the “jump in the water” solution?), he therefore must work for a reality TV show and was transported there by helicopter. So all he needs to do is contact them by walkie-talkie to have them fly back to rescue him.

  32. i solved it instantly, but that’s because they told you how to do this on “How!”, the kid’s TV show on ITV in the 70′s, and I’m an old git.

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