Who lives in the city

Bob · 2012-05-20 05:39:05

hi MathsIsFun

Please have a look at

http://www.mathsisfun.com/puzzles/who-l … city-.html

Thanks,

Bob

darpanap · 2012-05-20 17:21:19

hello

The solution given on this website for the puzzle "who lives in the city" is wrong. Please check.

I have given my solution for this puzzle.

Name TV Prog Destinations Age Hairstyle Where they live
Bob Simpsons France 46 Bald Town
Rachel Corrie Italy 21 long youth hostel
Keeley Desperate Housewives Africa 52 Afro Village
Elish coronation street England 81 curly Farm
Amy eastenders Australia 14 Straight City

Bob · 2012-05-20 19:31:05

hi darpanap

What? No Neighbours?

The setter goes to a school in England; so would know that Corrie is a common slang term for Coronation Street.

Thanks for reminding me.

MIF: The wording for question needs an edit, too. It'd be a shame to drop the term Corrie, so I suggest that, in the preamble, it has this alternative name in brackets to clear up the confusion.

Bob

MathsIsFun · 2012-05-20 23:35:07

Thanks bob, will add the Corrie thing.

What about the solution?

anonimnystefy · 2012-05-20 23:43:14

Hi MIF

You could add the condition "The 21-year-old is next to Eilish",which would make it non-ambiguous. Otherwise it has three solutions.

Bob · 2012-05-20 23:56:31

Good suggestion.

I'll go along with that.

Bob

anonimnystefy · 2012-05-21 00:09:27

That is the only one I have found so far that removes the other two possibilities. You can also exchange "21-yr-old" for "person who lives in the youth hostel".

MathsIsFun · 2012-05-21 09:09:09

Excellent. I will amend.

anonimnystefy · 2012-05-21 09:30:09

I'm glad we got a solution to th problem. Nice puzzle!

phrontister · 2012-05-28 04:44:55

Hi,

The solution on the MIF puzzle page is still incorrect, as it doesn't agree with the last clue: "The 21-year-old is next to Eilish". The 21-year-old is shown as being in position 2 and Eilish in position 5.

I get two solutions (see images).

Comparing the two solutions and choosing the first (the one where Eilish lives in the city) to be the one to alter, changing the last clue to "The 21-year-old is next to Keeley" would give a unique solution, I think...but I should check that out in case the change starts off a chain reaction. I'll do that later.

Last edited by phrontister (2012-05-28 05:43:00)

phrontister · 2012-05-28 11:52:00

This is the worksheet I use, updated to include my change to the last clue.

I haven't tested my clue change yet to see if it works.

Last edited by phrontister (2012-05-28 15:55:55)

Bob · 2012-05-28 19:32:47

hi phrontister,

I think MIF has changed the puzzle wording since Stefy and I worked out our answers; at least, I hope so, because my answers don't work now and yours do. I'll check your suggestion and report back later.

LATER EDIT:

I've checked your two solutions in post #10 and agree with both.

I also agree with your extra clue and yes, it leads to one solution, Eilish lives in the city.

Thanks for your input.

Bob

phrontister · 2012-06-01 11:48:46

Hi Bob,

bob bundy wrote:

I also agree with your extra clue and yes, it leads to one solution, Eilish lives in the city.

I've finally got around to checking that clue change of mine. Well, unless my reasoning is flawed, it opens the gate to multiple solutions...more than 2, in fact.

Here are two more solutions to add to the one in post #10 (there are more, but I can't be bothered showing them all). I've included images of my worksheets for these two solutions.

Some other clue change is needed to obtain a unique solution...I'll look into that some more later.

Last edited by phrontister (2012-06-01 12:02:06)

Bob · 2012-06-01 19:05:59

hi phrontister,

Multiple solutions?

My method for solving finds all solutions (if I don't make a mistake) and I found just two.

So adding an extra clue cannot make more solutions. Were you changing a clue?

Bob

phrontister · 2012-06-02 07:04:23

Hi Bob,

So adding an extra clue cannot make more solutions. Were you changing a clue?

I didn't actually add a clue, I only changed stefy's additional clue from "The 21-year-old is next to Eilish" to "The 21-year-old is next to Keeley" (see posts #5 and #10). All other clues remain unaltered (I copy/pasted them from MIF's page into my spreadsheet).

Below are two more solutions, which now makes five (including one from post #10 and two from post #13).

I haven't done an exhaustive check (only exhausting), but I think there aren't any more solutions.

So the hunt for a set of clues that leads to a unique solution is still on.

anonimnystefy · 2012-06-02 07:16:00

I have found out what is wrong with your first solution.You didn't take in the 3rd clue:

"* The person who watches the Simpsons is next to the person who lives in a youth hostel"

It leaves correct only your 2nd solution.

phrontister · 2012-06-02 08:10:01

Thanks, stefy.

I'm not sure how that 'solution' snuck in, because I've only kept my worksheets for the ones that I thought checked out as valid solutions and I can't find the worksheet for that one.

Anyway, that still leaves four solutions...unless I erred with those as well.

Last edited by phrontister (2012-06-02 08:15:11)

anonimnystefy · 2012-06-02 08:16:57

Hi phro

Can you give me those 4 solutions?

phrontister · 2012-06-02 12:17:20

Hi stefy...here they are again (they appear in posts #10, #13 & #15).

I re-checked them a few moments ago against MIF's clues, for which the only alteration is the change to your additional clue from "The 21-year-old is next to Eilish" to "The 21-year-old is next to Keeley".

Just to recap: Your additional clue is on the MIF page as part of the clue list, but the solution given there is incorrect (see my post #10). I found two correct solutions, though (which I also re-checked just now)...see images in post #10. In that same post I mentioned the reason for my clue change...which unfortunately hasn't worked.

anonimnystefy · 2012-06-02 12:27:25

My clue change was added to the clue list. Can I see your solutions with my clue?

phrontister · 2012-06-02 13:22:50

Hi stefy,

Here they are (same as the images in my post #10).

Ignore the following links (they don't exist, and I can't delete them):

Last edited by phrontister (2017-03-03 18:10:57)

anonimnystefy · 2012-06-02 13:53:44

All the clues check out. I have no idea what happened. What app are you using to graphically represent the clues?

MathsIsFun · 2012-06-02 14:12:24

Wow ... this is one powerful puzzle. Looking forward to a definitive solution. Even two solutions would be OK, I could post them both.

phrontister · 2012-06-02 14:54:22

Hi stefy,

I use Excel.

My puzzle layout is similar to those of this type that you can find in 'Logic Puzzles' magazines at newsagents. I've done a couple of dozen of them and this method works quite well for me...although it's pretty time-consuming. Maybe there are quicker ways, but this is the only one I've ever used (mainly because I don't know any other).

Hi MathsIsFun,

I'd like to try for a unique solution, but, as you can see, that may not be all that easy to achieve!

This is the largest of this type I've ever done, and changing or adding a clue in a puzzle this size can unexpectedly open doors that then need to be shut. The magazine-type puzzles that I've seen are usually no bigger than about half this one.

I'm hoping that my grid layout style may help me to identify a constraint for a unique solution.

anonimnystefy · 2012-06-02 19:51:18

Hi phro

Could you now show me what your solutions are for MIF's original puzzle?

Math Is Fun Forum

#1 2012-05-20 05:39:05

Who lives in the city

#2 2012-05-20 17:21:19

Re: Who lives in the city

#3 2012-05-20 19:31:05

Re: Who lives in the city

#4 2012-05-20 23:35:07

Re: Who lives in the city

#5 2012-05-20 23:43:14

Re: Who lives in the city

#6 2012-05-20 23:56:31

Re: Who lives in the city

#7 2012-05-21 00:09:27

Re: Who lives in the city

#8 2012-05-21 09:09:09

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#9 2012-05-21 09:30:09

Re: Who lives in the city

#10 2012-05-28 04:44:55

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#11 2012-05-28 11:52:00

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#12 2012-05-28 19:32:47

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#13 2012-06-01 11:48:46

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#14 2012-06-01 19:05:59

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#15 2012-06-02 07:04:23

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#16 2012-06-02 07:16:00

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#17 2012-06-02 08:10:01

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#18 2012-06-02 08:16:57

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#19 2012-06-02 12:17:20

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#20 2012-06-02 12:27:25

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#21 2012-06-02 13:22:50

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#22 2012-06-02 13:53:44

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#23 2012-06-02 14:12:24

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#24 2012-06-02 14:54:22

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#25 2012-06-02 19:51:18

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