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#26 2014-02-20 03:35:33

John E. Franklin
Member
Registered: 2005-08-29
Posts: 3,588

Re: Torpedos

No, I mean, I am getting a simpler answer and wondered if it had to do with that a ship can't sink 4 times at once???

I just set up a table like a truth table with values 0 to 4 in 3 columns like a child might do and I get 5/6th with 12 rows or
10/12 sinking.

Last edited by John E. Franklin (2014-02-20 03:37:36)


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#27 2014-02-20 03:37:58

bobbym
bumpkin
From: Bumpkinland
Registered: 2009-04-12
Posts: 109,606

Re: Torpedos

Hi;

Sure it is already figured in the above calculations. But there are more ways to sink then just being hit 4 times. That is why the answer given is larger than yours.


In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

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#28 2014-02-20 03:42:48

John E. Franklin
Member
Registered: 2005-08-29
Posts: 3,588

Re: Torpedos

What I mean is, are you treating the problem like a child, or are you stipulating other criteria, like you can't have 3 damages because 2 sinks it?


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#29 2014-02-20 03:52:33

bobbym
bumpkin
From: Bumpkinland
Registered: 2009-04-12
Posts: 109,606

Re: Torpedos

The solutions we gave take all of them into consideration. 1,2,3,4 hits or 2 damages.


In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

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#30 2014-02-20 04:17:38

John E. Franklin
Member
Registered: 2005-08-29
Posts: 3,588

Re: Torpedos

thank you.  I am starting to see that my answer may be flawful in that the 12 rows I haven't even told you of, are actually expandable to more rows and some rows I think will have more expansions than other rows, so I will have to redo my work, or at least continue it...  Thanks for getting me to think more.

I still think I'm doing it the wrong way, but will try another way soon.
Now I'm getting 45 rows and 40 are sinkable, giving 8/9 sink, but I think I'll keep trying until I get your number or until I am convinced of something else like hotdogs that postpone this...

Last edited by John E. Franklin (2014-02-20 04:30:55)


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#31 2014-02-20 04:26:59

bobbym
bumpkin
From: Bumpkinland
Registered: 2009-04-12
Posts: 109,606

Re: Torpedos

Hi;

Run a little computer program that simulates this and then ponder about the answer you will get.


In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

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#32 2014-02-20 04:54:20

John E. Franklin
Member
Registered: 2005-08-29
Posts: 3,588

Re: Torpedos

Okay, I got a 27 row list expandable to 81 by changing the last column from 0, 1 or 2.
And 0=miss, and 1=damage, and 2=sunk.
It became quite clear that providing these 81 combinations were all 1/81 of the time, then I could just count the rows
with 0 or 1 totals for the unsinking rows.
Doing this, I get:
0000, 0001, 0010, 0100, 1000, which is five rows.
So unsinking could be 5/81 and (81-5)/81 or 76/81 could be the sinkable probability.
Um. 
So
miss-miss-miss-miss
miss-miss-miss-damage
miss-miss-damage-miss
miss-damage-miss-miss
damage-miss-miss-miss
equals five ways out
of 81.
So I guess at this point
I wish I knew all those
other amazing methods,
but I have years to learn
these things if I can or
have the time and skill
and determination.


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#33 2014-02-20 05:01:25

bobbym
bumpkin
From: Bumpkinland
Registered: 2009-04-12
Posts: 109,606

Re: Torpedos

76 / 81 is correct.


In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

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#34 2014-02-20 05:07:26

John E. Franklin
Member
Registered: 2005-08-29
Posts: 3,588

Re: Torpedos

Hey, I was wondering.  What do you think would be a good way to proceed with this story of the torpedos.
Because I think I would like to learn more about this now that I also am getting 5/81 float, but more than
that fact is that when I got 45 rows, it was a haphazard approach, so I am very interested in not making the
same mistake again down the road, unless ofcourse someone brings me to my senses again.


igloo myrtilles fourmis

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#35 2014-02-20 05:14:03

John E. Franklin
Member
Registered: 2005-08-29
Posts: 3,588

Re: Torpedos

I knew you would probably suggest I analyze the incorrect answer with 45 rows and see if I missed 36 rows and so I did that and
now I have three more rows to add to my original 12 row way and I'm working on expanding that...

Yup, I found the 12 x 3 = 36 missing rows in my first approach.  Now I'm getting 81 again for the number of ways the shots can be fired, basically 3 x 3 x 3 x 3.

Wow, if this problem hadn't been 1/3 exactly for the probabilities, then I would have to learn some of your other methods.

So I will pose another problem in another thread I guess, if you approve that might get me to learn this better.
I'll wait a few minutes to see if you think we should just continue in this one though first...

Last edited by John E. Franklin (2014-02-20 05:18:39)


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#36 2014-02-20 05:31:47

bobbym
bumpkin
From: Bumpkinland
Registered: 2009-04-12
Posts: 109,606

Re: Torpedos

Hi;

Post in "Help Me" when you are ready.


In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

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