Great Interview Question

[Redhatcc]

Here is my idea lol...

If it is a school of sharks, they are in a group, swimming around the island as one single unit? You would get in the water when they are on the opposite side of the island, and swim in the same direction as the sharks at the same speed, you will never catch them and they will never catch you. Then wait until the fire is burnt out.

And if this matters, make a boat out of unburnt wood, then do the steps above.

Close?

[ricktendo]

I answer him with a question

Why is the island made entirely of concrete?

[gamehead200]

I guess that GrofLuigi and 5eraph were thinking as I was about fire traveling similar to ripples from rocks thrown in a pond - outward from the center in a circle. If that were true a firebreak wouldn't work, since as GrofLuigi stated:

"I can't imagine a situation where it won't spread towards me. If I start a fire in the middle, the two fires will cancel each other out on the other side, but 'my' fire will go towards me."

But that doesn't take into account wind, which will always drive a fire away from it faster than in can come toward it, so on the (assuming) flat concrete island it will go in mostly one direction, or at least in a spreading cone shape. And if there were absolutely no wind, it would indeed expand in a circle, but it would create wind blowing toward it from the updraft caused by the heat from the fire. You could then use that wind and create small fires at the edge of the expanding circle, where the greater heat from the larger fire would pull the other fires toward it creating a safe zone for you. Do I have the theory correct?

Cheers and Regards

Yeah, the wind is key here... I guess that's something else I forgot to mention in the original situation. Oops...

Here is my idea lol...

If it is a school of sharks, they are in a group, swimming around the island as one single unit? You would get in the water when they are on the opposite side of the island, and swim in the same direction as the sharks at the same speed, you will never catch them and they will never catch you. Then wait until the fire is burnt out.

And if this matters, make a boat out of unburnt wood, then do the steps above.

Close?

Let me ask you this... How fast can you swim? Definitely not as fast as a shark, I would think...

[Guest]

I guess that GrofLuigi and 5eraph were thinking as I was about fire traveling similar to ripples from rocks thrown in a pond - outward from the center in a circle. If that were true a firebreak wouldn't work

That was my thinking as illustrated in the crude image below.

I am the blue dot, my fire started at the yellow dot, and the lightning struck at the yellow lightning bolt. The black area is burned but safe. The green area is unburned. And the red outline on the burned area indicates the fire line that cannot be crossed or touched. As is evident in my image, I'm screwed with less time than I originally had if I hadn't started another fire.

But that doesn't take into account wind, which will always drive a fire away from it faster than in can come toward it, so on the (assuming) flat concrete island it will go in mostly one direction, or at least in a spreading cone shape. And if there were absolutely no wind, it would indeed expand in a circle, but it would create wind blowing toward it from the updraft caused by the heat from the fire. You could then use that wind and create small fires at the edge of the expanding circle, where the greater heat from the larger fire would pull the other fires toward it creating a safe zone for you.

Assuming that is correct, you cannot expect a layperson to know that information. If I were interviewing for a firefighter's position then this would be a fair question. It's not a fair question to ask of somebody you pulled off the street.

Yeah, the wind is key here... I guess that's something else I forgot to mention in the original situation. Oops...

I would not have arrived at the desired answer even if you had mentioned the wind. Specific knowledge was tested, not common sense as it should have been.

Good questions an interviewer should ask should either be directed toward information the prospective employee should already know, or general logic questions that rely on common knowledge that will reveal to the interviewer how the prospective employee thinks and arrives at conclusions. As I said above, this would be a good question to ask of a firefighter, not a network technician or car mechanic.

Edited April 10, 2010 by 5eraph

[cluberti]

Assuming that is correct, you cannot expect a layperson to know that information. If I were interviewing for a firefighter's position then this would be a fair question. It's not a fair question to ask of somebody you pulled off the street.

You miss the point of questions like this - it's not to get the correct answer, it's so the interviewer can "see" how the interviewee thinks, and what kind of mental horsepower he or she has. You get asked logic questions with less-than-obvious answers (and ridiculous situations) partially because they would never happen in real life, so you have to really think hard about your answers. You miss the point of the questions entirely.

Good questions an interviewer should ask should either be directed toward information the prospective employee should already know, or general logic questions that rely on common knowledge that will reveal to the interviewer how the prospective employee thinks and arrives at conclusions. As I said above, this would be a good question to ask of a firefighter, not a network technician or car mechanic.

Asking someone things they already know will only tell you certain things about a person. If you want to find out also how well they react to odd situations, or how someone thinks on their feet, asking questions you would reasonably expect an interviewee to know gets you nothing. Again, you miss the point of asking these types of questions in the first place - it's fairly common in a dev interview to get dev questions, logic questions, and interpersonal-type questions. Assuming you're a decent dev, and not a complete jerk, the only part that will be "hard" will be the logic questions, and it's something that can get you a job or lose you a job, honestly, as most other interviewees who make it past the first screening are also likely decent at their job (at least), and are problably decent people as well.

[Guest]

But I do understand all that, cluberti. gamehead200 was looking for a specific answer involving wind. Please read my previous response more carefully if you don't believe me.

[...] this isn't the answer.

the wind is key here...

Edited April 22, 2010 by 5eraph

[JustShootIt]

I got asked this in an interview once so that the interviewer could understand my thought process. The answer is actually extremely simple, but unfortunately, I wasn't able to get the right answer at the time.

Here goes...

You're stranded on an island made entirely of solid concrete (comment: unlikely, but OK) in the middle of the ocean. The island has nothing but trees on it. There is a school of sharks swimming around the island. While you're on one side of the island, a lightning bolt strikes a tree on the opposite side of the island and the tree catches fire. Slowly, but surely, the fire spreads from one tree to the next and makes its way towards you.

How do you survive?

I think that if an employer made a decision on such a ridiculous basis, I would go looney if I worked there. A pefect example of "business school thought"...someone who doesn't even know the job their employees do, while trying to tell them how to do it, because they don't have the brains to do even the simplest job themselves. Save me from that type!

[puntoMX]

Save me from that type!

Any way, a silly question will have a silly answer I would say (flame me! ), sooo: I will turn into a beaver and use my teeth to get that tree down, heck, I would not live long on some concrete with burned trees, I would take my last swim or stick my head out towards a shark to make it quick!