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## #1 2012-07-29 21:32:42

pRo9aMeR
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### Who has the purple door?

I've had lots of fun with the Einstein Puzzles on the MiF website, so much, in fact, that I wanted to create my own.

I use the Einstein puzzles in my English classes in Korea to let them relax but still have to use their English skills.

Here's the puzzle, please let me know what you think!  Any feedback/comments/criticism is welcomed!

Enjoy!

EDIT 1: August 6th 10:50am KST (Korean Standard Time) for clarification purposes
I'm not trying to trick anyone with the wording^^  Just challenge you.  Good Luck!
EDIT 2: forgot to rephrase the 'female teachers' part
EDIT 3: Aug. 31st to increase difficulty with phronister's help! (Note: I think I can make it slightly harder still, but not conclusive yet)
EDIT 4: Sept. 5th forgot to add the second question! oops!  and edited two more clues to make it harder, muwhahaha!
EDIT 5: Feb. 6th Final version!  (I hope~~)
EDIT 6: Feb. 27th a new final version as per post #44

THE PUZZLE:
Which teacher has the purple door?

There is a study hall with one entrance and at the end of the hall is one exit.
As you enter, there are 2 rows of classrooms - five on your left and five on your right.
Ten different teachers use these classrooms to teach ten different subjects, respectively.
Each classroom has a different number of students and a different colored door.
In addition, each class has a unique starting time and a unique ending time.
The clues below give the teachers' first names and surnames, along with other information:

1) Jerek's classroom is the last one on the right.
2) David's class starts at 6:30pm and ends at 8:45pm.
3) Jennifer's Chinese class has a white door.
4) Jessica's class is 3 hours and 15 minutes long and is next to Mr. Nest's class.
5) Joe's class is next to the Music class and the exit.
6) Matthew's class ends at 8pm.
7) Max teaches Literature and is next to Ryan's classroom.
8) Michaela's class is next to Mrs. Smith's class.
9) Mr. Adams' 30-student class is next to Mr. Bush's 29-student class.
10) Mr. Bentley teaches Medicine.
11) Mr. Johnson's class has a blue door and ends at 10:15pm.
12) Mrs. Franklin's class lasts for 3 hours.
13) Michelle's class ends at 7:45pm.
14) Mrs. Jackson's class is between Mr. Bentley's and Mr. Jones' and across from Mrs. Franklin's.
15) Mrs. Wyatt's classroom is next to the class with 19 students.
16) Ryan's class has 33 students and a red door.
17) The 16-student class has an orange door.
18) The 20-student class is in between the 19-student class and the 18-student class.
19) The 34-student class has a pink door.
20) The black and grey doors are next to each other and the black-door class starts at 5pm.
21) The class between Jerek's and the red door starts at 5:15pm.
22) The class that ends at 9:30pm is in between the red door and the Reading class.
23) The class that ends at 10pm is across from Mr. Bush's.
24) The first class on the left has 19 students.
25) The Grammar class is next to Mr. Jones' class.
26) The green door is across from the class that starts at 5pm.
27) The History class is next to the class that starts at 6:15pm.
28) The Listening class starts at 7pm.
29) The Medicine class starts at 6pm and has 33 students.
30) The Music class ends 45 minutes before the Chinese class ends.
31) The Speaking class ends 15 minutes after the Literature class begins.
32) The Speaking class starts 2 hours before the History class starts.
33) The Reading and Writing classes are next to the entrance.
34) The yellow door is across from the class that starts at 7:15pm.
35) There are a total of 255 students and the left side has 5 more students than the right side.
36) Two of the four three-hour-long classes have female teachers.
37) The 16-student class ends half an hour before Mr. Adams' class ends.

Last edited by pRo9aMeR (2013-02-27 17:38:07)

## #2 2012-07-29 21:36:40

bob bundy
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### Re: Who has the purple door?

hi pRo9aMeR

Welcome to the forum!

Thanks for the puzzle.  It looks like quite a challenge so it may take a while.  eeekkk!

Bob

You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei

## #3 2012-08-05 23:34:07

phrontister
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### Re: Who has the purple door?

Hi pRo9aMeR,

I've started to have a look at the puzzle, but before I get further into it I'd like some clarification about the following:

1. Clue 7: Shouldn't "Max teaches" read "Max learns"? (or similar)

2. Clue 17: Shouldn't "Ryan has 38 students" read "Ryan's class has 38 students"?

3. Clue 38: By "girls" I guess you meant female teachers. In the sense that would normally apply to a puzzle like this, the term 'girls' would be used to apply to students, not teachers. To one particular MIF member - one of an extremely advanced age - a female of any age would be a 'girl'. But not to me.

4. Assuming that my change to Clue 7 is correct (so that Max is a student and not a teacher), there are then ten different student names. If none of those students share classes with each other, should we have been given that information in advance (but maybe worded differently), or is that knowledge not required to solve the puzzle?

Last edited by phrontister (2012-08-06 02:13:16)

"The good news about computers is that they do what you tell them to do. The bad news is that they do what you tell them to do." - Ted Nelson

## #4 2012-08-06 02:54:07

pRo9aMeR
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### Re: Who has the purple door?

Hi phronstister...I guess I should've clarified those points.

1 & 2. All the first names are the first names of the teachers...Each of the 10 teachers has a first name and last name listed somewhere in the clues.

3. I will change it to say 'female' instead of 'girl'.

4. see above

When I gave this and other einstein puzzles to my students, they were all accompanied by a table which helps them organize the information.  Do you want me to post that table?

Also, should I repost the puzzle with the 'girl->female' and clarification of teachers' first and last names?

## #5 2012-08-06 07:21:55

MathsIsFun

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### Re: Who has the purple door?

Wow ... what a Puzzle!

"The physicists defer only to mathematicians, and the mathematicians defer only to God ..."  - Leon M. Lederman

## #6 2012-08-06 09:44:43

phrontister
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### Re: Who has the purple door?

Hi pRo9aMeR,

1 & 2. All the first names are the first names of the teachers...Each of the 10 teachers has a first name and last name listed somewhere in the clues.

Ah...now that was an option that didn't occur to me! Yes, that information needs to be stated in the puzzle.

3. I will change it to say 'female' instead of 'girl'.

eg, "two of which have female teachers".

Do you want me to post that table?

Some solvers might like to see it, but others may prefer to try to solve the puzzle unaided. My preference is the latter. I've already created my own table in Excel, which is quite simple to do.

You may find posting the table to be difficult right now as I'm pretty sure that members of 'Novice' status can't post links or images. After some more posts (not sure of exactly how many) - and maybe there is a time factor too (not sure) - those restrictions are removed. That's part of the anti-spamming control here.

Also, should I repost the puzzle with the 'girl->female' and clarification of teachers' first and last names?

I think it would be best to edit your first post - which is the first one seen by anyone new to the thread - rather than post a corrected version in a subsequent post.

"The good news about computers is that they do what you tell them to do. The bad news is that they do what you tell them to do." - Ted Nelson

## #7 2012-08-06 22:24:18

phrontister
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### Re: Who has the purple door?

Hi pRo9aMeR,

Last edited by phrontister (2012-08-07 00:13:36)

"The good news about computers is that they do what you tell them to do. The bad news is that they do what you tell them to do." - Ted Nelson

## #8 2012-08-06 23:11:04

pRo9aMeR
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### Re: Who has the purple door?

EDIT1: Thanks for hiding this bobbym!

Last edited by pRo9aMeR (2012-08-07 00:46:27)

## #9 2012-08-06 23:21:08

bobbym

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### Re: Who has the purple door?

Hi pRo9aMeR;

I have hidden it for you.

In mathematics, you don't understand things. You just get used to them.
I have the result, but I do not yet know how to get it.
All physicists, and a good many quite respectable mathematicians are contemptuous about proof.

## #10 2012-08-06 23:37:52

phrontister
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### Re: Who has the purple door?

Hi pRo9aMeR,

Oops! >blush< I see what I did. I leapt to conclusions before closing all the doors! Please forgive me.

Btw, I take it that by "across from" you mean 'opposite'. (eg, the second class on the left would be 'across from' the second class on the right). I've heard that phrase here in Australia, but only very rarely. I googled it and found that it's in more common use in America. So to me, "opposite" would have been clearer, but I'm not sure that it would need changing.

You can hide certain parts of your posts, as I described here and in the post after that.

Last edited by phrontister (2012-08-06 23:45:31)

"The good news about computers is that they do what you tell them to do. The bad news is that they do what you tell them to do." - Ted Nelson

## #11 2012-08-07 00:04:14

pRo9aMeR
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### Re: Who has the purple door?

No worries!  You are forgiven! haha..

and yes, you are correct, across from means opposite like you explained.  To reiterrate, the second class on the left and opposite (or across from) the second class on the right.

Also, now I know how to hide parts of a post^^ ty!

## #12 2012-08-07 00:18:21

phrontister
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### Re: Who has the purple door?

To prevent my blunder from spoiling things for others, it would probably be best for you to delete from your post #8 the last paragraph of your quotation. I've deleted that paragraph from my post #7.

The rest probably wouldn't spoil anything for anybody.

And you could also hide my quote in your post. Use the 'Preview' button before making your final submission to make sure your post is going to turn out the way you want it to.

Last edited by phrontister (2012-08-07 00:21:14)

"The good news about computers is that they do what you tell them to do. The bad news is that they do what you tell them to do." - Ted Nelson

## #13 2012-08-08 04:52:13

phrontister
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### Re: Who has the purple door?

Hi pRo9aMeR,

Solved it!

That was one of the most enjoyable puzzles I've ever done!

It was very challenging because of the myriad of components, which all went to make it extremely interesting so that once I started it, I just couldn't put it down.

That must have taken quite some time to compose, I reckon. Tremendous effort! Well done!!

Thanks for posting it.

Now that I've solved it, would you mind posting that table you mentioned in post #4? Because of your 'Novice' status you probably won't be able to upload an image of it or post a live link to it like I have of the solution, but if you have a download location (eg, a file host) of the table's file, could type the link into a post for me to copy and paste into my browser? That should work well enough for now. I'd be interested in having a look at it. Thanks.

Last edited by phrontister (2012-08-08 05:04:31)

"The good news about computers is that they do what you tell them to do. The bad news is that they do what you tell them to do." - Ted Nelson

## #14 2012-08-08 10:30:56

pRo9aMeR
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### Re: Who has the purple door?

Well done sir phrontister!

After solving and resolving the puzzle, I think it's possible to find the solution a couple clues before everything is filled in, so I'd like to rework the end of the puzzle's clues so that everything is necessary.
Also, I know there's at least one part of a one clue that is redundant so after I fiddle around with it some more I'll repost the final copy.
The whole thing took me about 3 or 4 hours to do over two days.
EDIT: 3-4 hours is grossly incorrect...I thought about it-I think it took me about 10-12 hours over two days. I remember starting Saturday evening and spending most of Sunday afternoon to finish it.

I will try and post the table later today, i just got to work and class starts soon^^

Cheers!

Last edited by pRo9aMeR (2012-08-09 18:58:41)

## #15 2012-08-08 19:31:26

phrontister
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### Re: Who has the purple door?

Hi pRo9aMeR,

Yes, the solution (ie, the answer to the puzzle title's question) can be found before solving all components. Ideally, that shouldn't be possible, but as there's so little left to fill at the end I didn't feel cheated at all (unlike with some puzzles that 'solve' waaay before the end).

A couple of things I like about this puzzle too that make it different from others I've done are:
- the inclusion of some arithmetic, and
- that some initial component lists are incomplete as they're waiting for info from somewhere down the solution track.

"The good news about computers is that they do what you tell them to do. The bad news is that they do what you tell them to do." - Ted Nelson

pRo9aMeR
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## #17 2012-08-14 01:44:10

phrontister
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### Re: Who has the purple door?

Hi pRo9aMeR,

Last edited by phrontister (2012-08-14 13:09:54)

"The good news about computers is that they do what you tell them to do. The bad news is that they do what you tell them to do." - Ted Nelson

## #18 2012-08-17 03:42:44

phrontister
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### Re: Who has the purple door?

Hi pRo9aMeR,

I've had a go at changing the puzzle to make all of the clues necessary for the solution, but I gave up because one change led to another and the whole thing was turning into alphabet soup!

The original puzzle's ending basically splits into two, thus enabling an early solution by choosing the door-colour route, and I just couldn't find a simple enough change to prevent that from happening while retaining the integrity of the original puzzle and all of its appealing features.

However, by adding a question (which I've seen done with other similar puzzles) and changing a couple of clues (#31 and #34), I may have found a satisfactory alternative.

Here's what I came up with:

Q. Which teacher has the purple door and which subject starts first?

There is a study hall with one entrance and at the end of the hall is one exit.
As you enter, there are 2 rows of classrooms - five on your left and five on your right.
Ten different teachers use these classrooms to teach ten different subjects, respectively.
Each classroom has a different number of students and a different coloured door.
In addition, each class has a unique starting time and a unique ending time.
The clues below give the teachers' first names and surnames, along with other information:

1) Jerek's classroom is the last one on the right.
2) David's class starts at 5:45pm and ends at 8:30pm.
3) Jennifer's Chinese class has a white door.
4) Jessica's class is 2 hours and 15 minutes long and is next to Mr. Nest's class.
5) Joe's class is next to the Music class and the exit.
6) Matthew's class ends at 8pm.
7) Max teaches Literature and is next to Ryan's classroom.
8) Michaela's class is next to Mrs. Smith's class.
9) Michelle's class has 2 fewer students than the Literature class.
10) Mr. Adams' 19-student class is next to Mr. Bush's 27-student class.
11) Mr. Bentley teaches Medicine.
12) Mr. Johnson's class has a blue door and ends at 9:30pm.
13) Mrs. Franklin's class lasts for 3 hours.
14) Mrs. Jackson's class ends at 9:45pm and is next to a class that ends 2 hours earlier.
15) Mrs. Jackson's class is between Mr. Bentley's and Mr. Jones' and across from Mrs. Franklin's.
16) Mrs. Wyatt's classroom is next to the class with 30 students.
17) Ryan's class has 38 students and a red door.
18) The 16-student class has an orange door and is next to the exit.
19) The 22-student class is in between the 30-student class and the 18-student class.
20) The 34-student class has a pink door and is on the left side.
21) The black and grey doors are next to each other and the black-door class starts at 5pm.
22) The class between Jerek's and the red door starts at 7pm.
23) The class that ends at 10pm is in between the red door and the Reading class.
24) The class that ends at 8:45pm is across from Mr. Bush's.
25) The first class on the left has 30 students.
26) The Grammar class is next to Mr. Jones' class.
27) The green door is across from the class that starts at 5pm.
28) The History class is next to the class that starts at 6:15pm.
29) The Listening class starts at 6:45pm and is next to a class that lasts for 3 hours.
30) The Medicine class starts at 6pm and has 38 students.
31) The Music class ends 2 hours before the Chinese class ends.
32) The Speaking class ends when the Literature class begins and is on the same side.
33) The Speaking class starts an hour before the History class starts.
34) The Medicine class is on the right.
35) The Reading and Writing classes are next to the entrance.
36) The yellow door is not next to the class that starts at 5:30pm.
37) There are a total of 255 students and the left side has 5 more students than the right side.
38) Two of the four classes that are 3 hours long have female teachers.

I think this version is quite tricky to solve.

If these changes work and you're happy with them, would you consider asking MathsIsFun to include the puzzle in MIF's Einstein puzzles? I reckon it would be a worthy entry!

Let me know what you think.

Cheers!

Last edited by phrontister (2012-08-19 23:20:23)

"The good news about computers is that they do what you tell them to do. The bad news is that they do what you tell them to do." - Ted Nelson

## #19 2012-08-19 21:45:58

pRo9aMeR
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### Re: Who has the purple door?

I've been very busy IRL but just saw you took the initiative!
After looking it over, however, I've found a problem...
If you take out the original #9 (Michelle's class has 2 less students than the literature class) then there are only three female first names within the clues!
I will continue to solve it assuming the original #9 is still in the puzzle and see how long it takes me^^

## #20 2012-08-19 22:57:15

phrontister
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### Re: Who has the purple door?

Oops! Yes, you're right. I overlooked that.

Might as well reinstate the original #9, so I'll put it back into my previous post. That then also changes the numbering back to the original.

Reinstating that clue only makes the puzzle a little easier to solve.

EDIT: I'm pretty sure that #9's not needed (and without it the difficulty level goes up a bit, which is a plus), so if you want to delete it an idea for including her name in the puzzle would be to do it where it doesn't affect anything...eg, by changing #11 to "Mr. Bentley teaches Medicine (although Michelle had wanted to)." Maybe that's a bit silly, but it was the first thought that popped into my head.

Last edited by phrontister (2012-08-19 23:28:44)

"The good news about computers is that they do what you tell them to do. The bad news is that they do what you tell them to do." - Ted Nelson

## #21 2012-08-20 03:05:09

pRo9aMeR
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### Re: Who has the purple door?

clue 31 (The Music class ends 2 hours before the Chinese class ends.) should read 1 hour, not 2 hours.

clue 34 (The medicine class is on the right) is unncessary.

And yes, clue 9 (Michelle's class has 2 fewer students than the literature class) is unncessary aside from the name.  Trying to figure out a way to work it in somewhere else.

Also, clue 29 (The listening class starts at 6:45pm and is next to a class that lasts for 3 hours) can be truncated to just (The listening class starts at 6:45pm).

That's all I got for now.^^

## #22 2012-08-20 11:53:09

phrontister
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### Re: Who has the purple door?

Hi pRo9aMeR

"The good news about computers is that they do what you tell them to do. The bad news is that they do what you tell them to do." - Ted Nelson

## #23 2012-08-24 18:53:44

pRo9aMeR
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### Re: Who has the purple door?

Last edited by pRo9aMeR (2012-08-24 19:31:26)

## #24 2012-08-24 19:25:17

phrontister
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### Re: Who has the purple door?

"The good news about computers is that they do what you tell them to do. The bad news is that they do what you tell them to do." - Ted Nelson

## #25 2012-08-31 18:46:57

pRo9aMeR
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### Re: Who has the purple door?

edited the OP puzzle^^

GOOD LUCK HAVE FUN EVERYONE!

Last edited by pRo9aMeR (2012-08-31 20:21:39)