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#6451 Re: Help Me ! » Markov Chains Problem » 2005-05-27 01:06:07

Indeed, if you are looking at one car owner, he will be on his "6 Year car" even after 8 years !

But we are looking at a large population here, I imagine, who are changing their cars every day.

Possible future for Large Car Owners (Year 0,3 and 6):

LLL
LLS
LSL
LSS

The question is for just one car owner, though. But it does not say how long the owner has had his present car.

So, he/she may exchange his car later today! Or not for 3 years.

#6452 Re: Help Me ! » Markov Chains Problem » 2005-05-27 00:35:47

Just for Fun, I worked out that matrix "P" where

P^3 = [0.6 0.25]
          [0.4 0.75]

It is (approximately):

[0.818    0.114]
[0.182    0.886]

So, what is P^6 ?

[0.460    0.338]
[0.540    0.662]

And P^8 is:

[0.422    0.362]
[0.578    0.638]

And P^9 is

[0.411    0.369]
[0.589    0.631]

There is some drift due to calculation accuracy, but if you worked P out more accurately you may have something workable. But  there may well be a rigorous way to do this rather than my "hey, lets use Excel and see what we get" approach smile

#6454 Re: Help Me ! » Markov Chains Problem » 2005-05-26 22:27:51

OK, well, we still have your "8 year" problem ...

... you could cheat and work out the probabilites at 6 and 9 and ratio in between.

Or, you could work out an equivalent matrix that works on 1 year intervals.

In other words, what is the Matrix "P" where:

P^3 = [0.6 0.25]
          [0.4 0.75]

(This is just an off-the-cuff idea, may not be rigorous)

#6455 Re: Help Me ! » Markov Chains Problem » 2005-05-26 22:21:20

Hi, maths_buff.

Markov chains are not my specialty, I am hoping that Milos or one of the other members is better versed in these than I am.

Having said that, I think your probability matrix needs to be transposed:

            L    S
S = L [ 0.6   0.25 ]
      S [ 0.4   0.75 ]

So, if someone owns a large car at time 0 we will have

x(0) = [1]
          [0]

at time 1 (3 years hence):

x(1) =  [ 0.6   0.25 ] [1]  = [0.6]
           [ 0.4   0.75 ] [0]     [0.4]

at time 2 (6 years hence):

x(2) =  [ 0.6   0.25 ]^2  [1] =  [ 0.46   0.3375 ]  [1]  = [0.46]
            [ 0.4   0.75 ]      [0]     [ 0.54   0.6625 ]  [0]     [0.54]

(Which has the values you had already mentioned)

#6458 Re: Puzzles and Games » Hi? » 2005-05-26 19:02:43

Oooohh .. a PUZZLE !

(6*6+6)/6 = 7  ...no

(6+6)/6 + 6 = 8  ...no

#6459 Re: Guestbook » algebra » 2005-05-26 11:05:32

We can help you - can you be more specific?

#6460 Re: Guestbook » Maths » 2005-05-26 09:48:28

Thank you so much!  That makes me so happy to read.

#6461 Re: Help Me ! » Last one hopefully » 2005-05-26 09:45:22

cool_me, you are genius ...

... I think hmm

#6463 Re: Maths Is Fun - Suggestions and Comments » Can we have a "general discussion" forum? » 2005-05-26 09:33:43

Vote:

The Mad Mathematicians Muddlings
Dark Discussions
Fun Forum
The Hangout
Cafe Infinity
The Set of All Topics

#6464 Re: Puzzles and Games » Horse race » 2005-05-26 00:52:39

smile

Go on, draw the lines, then!

#6466 Re: Help Me ! » Problem » 2005-05-25 21:37:28

The guys who posed it said "yes you can use the main signs add subtract multiply, divide not to sure weather too treat it as a logic problem?"

It seems to me that "Logic Problem" is a clue. It may not be solvable, I don't know.

#6468 Re: Help Me ! » Puzzling Puzzle » 2005-05-25 09:41:42

Is that right? LOL !!

Do I get a prize for answering it, then?

#6469 Re: This is Cool » this is fun » 2005-05-25 09:34:45

Perhaps if we used some Algebra on it

Start With: 1+1=x
Subtract x from both sides: 1+1-x=x-x
Subtract 1 from both sides: 1+1-x-1=x-x-1
Simplify: 1-x=-1

I think that is as far as I can simplify it.

#6470 Re: Puzzles and Games » Horse race » 2005-05-25 09:30:45

"Think Outside The Square!"

#6471 Re: Guestbook » hiya:d:p » 2005-05-25 09:29:12

And thank YOU very much for taking the time to write such a nice note.

#6472 Re: Guestbook » Mr Underdown Yay!!!!!!!!!! » 2005-05-25 00:28:20

He must be a good teacher to have such a nice recommendation.

#6473 Re: Help Me ! » Problem » 2005-05-24 23:10:40

Rats, you mean it isn't solved?

Well, then, we shall try harder ...

#6474 Re: Guestbook » Maths » 2005-05-24 21:32:16

We can ALL help you, rivali. Just ask a question!

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