[chbot] Choc Fish Challenge #5

jimmy allen jimmy1248 at gmail.com
Sun Sep 4 22:41:51 BST 2011


Hello

I am say approx 8 km

Here is some rough maths

d = 2 l Ln x

where
d is total distance traveled
l  - 1Km
Ln - natural log
x - number of wires

I say approx 10Km for 300 wires

Jimmy

On 9/5/11, m.beckett at amuri.net <m.beckett at amuri.net> wrote:
> Gents
> We have had a hack at this at work.
> We work out 4km required to label both ends.
>
> If you want the jumpering undone so they become individual, it needs a
> 5th km.
>
> We can explain how, but its a long email, and the phones keep ringing.
>
>
> Mark
>
>
> On Sun, 4 Sep 2011 21:55:00 +1200, Synco Reynders wrote:
>> Hi Mike,
>> I see you're a fit (or going to be a fit) guy after doing this... Cos
>> the next job your the boss has is a 300 wire cable <very subtle hint>
>> :-).
>> Nice try, but you may need a bit more optimisation.
>> /s
>>
>> On 4 September 2011 21:44, Michael Field <hamster at snap.net.nz> wrote:
>>> I've made a start.... this is flawed (at the end of step 2 we
>>> haven't
>>> definitively identified the bundles at the far end) but might
>>> inspire
>>> somebody. My guess is that you need to use uneven wire counts in
>>> each bundle
>>> you can glean more information....
>>>
>>> But I'm pretty sure that the divide into three groups and wiring up
>>> two is
>>> the correct starting point...
>>>
>>> Mike
>>>
>>> First step
>>> Separate the cables into 3 bundles of 40, short all cables in the
>>> bundle
>>> together Connect each end of the battery terminals to one bundle of
>>> 40
>>> (leaving one bundle unconnected).
>>>
>>> Walk to the other end.
>>>
>>> Connect light to a random wire, and try to get a circuit by
>>> connecting to
>>> each of the other wires. If nothing lights, try another wire.
>>>
>>> When you get a light, you will then be able to move one jumper
>>> around to
>>> find which 39 other wires are also in that bundle. Do the same with
>>> the
>>> other terminal of the bulb.
>>>
>>> You will then have three bundles of 40. One you will be know more
>>> about
>>> (it's not connected at the other end) but you won't know which
>>> bundle is
>>> connected to the positive terminal, and which is to the negative (oh
>>> for an
>>> LED or meter).
>>>
>>> Second step
>>> For each bundle of 40, divide it into two sets of 20, and jumper
>>> together.
>>> Jumper two bundles of 20 from one of those connected to one of the
>>> battery
>>> terminals together, jumper each bundle of 20 from the unconnected
>>> pair to a
>>> bundle of 20 that is connected to the battery.
>>>
>>> Walk back to the other end
>>>
>>> Use the bulb in series with the battery to separate the starting end
>>> into 6
>>> bundles of 20.  you will also be able to work out which bundle was
>>> connected
>>> to which battery terminal, accurately identifying both ends of the
>>> bundle.
>>>
>>> Label each cable.
>>>
>>> Step 3 & 4
>>> Deal out the cables again 3 or 4 from each bundle of 20, into new
>>> bundles of
>>> 40. Repeat. The above process, walking another two trips
>>> This will allow you to divide the cables into 36 bundles of three or
>>> four.
>>>
>>> Step 5 & 6
>>> Deal out the cables again bundles of 3 or for , into new bundles of
>>> 40.
>>> Repeat. The above process, walking another two trips
>>> This will allow you to identify individual cables.
>>>
>>>
>>> On 4/09/2011 7:48 p.m., Synco Reynders wrote:
>>>
>>> As I was pulling through some wires today I remembered this classic
>>> challenge...
>>>
>>> A 120 wire cable has been laid firmly underground between two
>>> telephone exchanges located 1km apart.
>>> After the cable was laid it was discovered the individual wires are
>>> not labeled. There is no visual way of knowing which wire is which
>>> and
>>> thus connections at either end is not immediately possible.
>>> As trainee technician your boss has asked you to sort it out and
>>> identify / label the wires at both ends. You only have a battery and
>>> light bulb to test continuity and tape/pen for labeling the wires.
>>>
>>> What is the shortest distance in kilometers you will need to walk to
>>> correctly identify and label each wire?
>>>
>>>
>>>
>>>
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>>>
>>
>> _______________________________________________
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>>
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>
>
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>
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