Safe Speed Forums

Quick quiz to get those brain cells working.

You have a cube. (well, you don't actually have it or have seen it, otherwise you'd know the answer, but it exists nonetheless)
What you know about the cube is that it's of random size, and its volume is equal to or less than 8 cubic centimetres.
What's the probability of its volume being equal to or less than 1 cubic centimetre?

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Only when ideology, prejudice and dogma are set aside does the truth emerge - Kepler

Not a good question!

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http://kalvis.com/

Surely there's no way of knowing unless you have some information about the distribution of cube sizes. If the smallest cubes in the population were 1.1cm in height, then the probability would be zero.

It's like asking if you have an 80kg adult human being, what's the probability of a random adult human being weighing 10kg or less.

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"Show me someone who says that they have never exceeded a speed limit, and I'll show you a liar, or a menace." (Austin Williams - Director, Transport Research Group)

Any views expressed in this post are personal opinions and may not represent the views of Safe Speed

I did say that it's of random size, ie the distribution of sizes is completely random.

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Only when ideology, prejudice and dogma are set aside does the truth emerge - Kepler

Indeed true. However, assuming distributions with minimum information etc, can fill the gap. In some situations, the results work out rather well.

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http://kalvis.com/

Let's just say that the population size is 1, ie it's a one-off cube made to a randomly-selected size.

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Only when ideology, prejudice and dogma are set aside does the truth emerge - Kepler

That comment is content free!

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http://kalvis.com/

I just don't know how better to put it

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Only when ideology, prejudice and dogma are set aside does the truth emerge - Kepler

You could post the answer, and then we could work out a question.

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http://kalvis.com/

Are you assumimg that the sides can only be in exact centimeters? If that was the case, I would say the answer is 50%

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My views do not represent Safespeed but those of a driver who has driven for 39 yrs, in all conditions, at all times of the day & night on every type of road and covered well over a million miles, so knows a bit about what makes for safety on the road,what is really dangerous and needs to be observed when driving and quite frankly, the speedo is way down on my list of things to observe to negotiate Britain's roads safely, but I don't expect some fool who sits behind a desk all day to appreciate that.

No, the sides can be in any units

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Only when ideology, prejudice and dogma are set aside does the truth emerge - Kepler

I'll stick my neck out. If by random you mean equally distributed then the answer is 12.5%

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When I see an adult on a bicycle, I do not despair for the future of the human race. H.G. Wells
When I see a youth in a motor car I do d.c.brown

Hmm.
To look at it another way, we know the length is 2cm or less, so what is the probability of its length being equal to or less than 1cm?

Is this something clever to do with linear or cubed distributions?

The "randomly-selected size" implies a flat distribution - but the "size" of what: the volume of the length?

Going out on a limb, and assuming the 'length' approach (seems right to me): I would say grabby was correct, but for the wrong reason.

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Views expressed are personal opinions and are not necessarily shared by the Safe Speed campaign

Grabby is right, it is 50% (or 0,5 for the pedantic). The unit's don't matter.
In answer to Steve, it doesn't matter whether the "size" is in volume or length.
But can someone explain this apparent paradox?

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Only when ideology, prejudice and dogma are set aside does the truth emerge - Kepler

I think it does matter. I believe DCB's answer was based on a flatly-distributed size of volume.

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Views expressed are personal opinions and are not necessarily shared by the Safe Speed campaign

It doesn't, but I'd like to see if someone else can say why it doesn't, before I explain it.

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Only when ideology, prejudice and dogma are set aside does the truth emerge - Kepler

I stand by my answer. The question was posed in terms of volume so any reference to length of sides is spurious

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When I see an adult on a bicycle, I do not despair for the future of the human race. H.G. Wells
When I see a youth in a motor car I do d.c.brown

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When I see an adult on a bicycle, I do not despair for the future of the human race. H.G. Wells
When I see a youth in a motor car I do d.c.brown

I'll post the answer sometime tomorrow.

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Only when ideology, prejudice and dogma are set aside does the truth emerge - Kepler

While I'm scratching my head can I just say there are no stupid questions, only stupid answers....

I could send this to someone I know will know, but I have a feeling it'll be over soon...


No! Tease us Pete!!!

It's like making love, you don't just go for the...

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The views expressed in this post are personal opinions and do not necessarily represent the views of Safe Speed.
You will be branded a threat to society by going over a speed limit where it is safe to do so, and suffer the consequences of your actions in a way criminals do not, more so than someone who is a real threat to our society.