# Math Is Fun Forum

Discussion about math, puzzles, games and fun.   Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫  π  -¹ ² ³ °

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## #1 2017-12-11 07:40:13

Roger L
Member
Registered: 2017-12-11
Posts: 1

### Correct Answer to 12 Days of Christmas Puzzle

The correct answer to this puzzle should be 376 instead of 364 as stated in the answer. This is because in the first day of Christmas you receive a partridge but you also receive a pear tree since the partridge is IN the pear tree. At the end you should add 12 pear trees.

Hope my assumption is correct.

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## #2 2017-12-11 15:03:59

Jai Ganesh
Registered: 2005-06-28
Posts: 47,158

### Re: Correct Answer to 12 Days of Christmas Puzzle

Hi Roger L,

You have not given the text of the puzzle. Please provide the entire problem.

It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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## #3 2017-12-11 21:46:32

Alg Num Theory
Member
Registered: 2017-11-24
Posts: 693
Website

### Re: Correct Answer to 12 Days of Christmas Puzzle

http://www.mathsisfun.com/puzzles/12-da … ution.html

It’s a partridge IN a pear tree, not partridge AND a pear tree. The tree provides a setting for the bird to be in and is not counted as a separate gift.

The solution is involves a sum of triangular numbers

[list=*]
[*]

[/*]
[/list]

where

[list=*]
[*]

[/*]
[/list]

Last edited by Alg Num Theory (2017-12-11 21:53:48)

Me, or the ugly man, whatever (3,3,6)

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## #4 2017-12-11 22:00:18

Bob
Registered: 2010-06-20
Posts: 10,507

### Re: Correct Answer to 12 Days of Christmas Puzzle

hi Roger L

Welcome to the forum.

Hhhmmm.  Interesting interpretation.  What constitutes a 'present' ?  As the geese are laying should we also count the eggs ?  And if the ladies are wearing jewelry should we also count those items ?  This could go on for some time.

And is it acceptable to 'give' people as presents anyway ?  Sounds illegal to me.

This puzzle was used back in the days of GCSE coursework as an investigation.  The usual format for these was (1) state a problem (2) get some data (3) look for a formula (4) prove it (5) consider extensions.  You seem to have leapt to step (5).  But you have to use some algebra and prove it to get the higher marks.

Thanks to Alg Num Theory for the formula.

ganesh: It's from the MIF puzzles:

http://www.mathsisfun.com/puzzles/12-da … stmas.html

Best wishes and a happy Christmas to all.

Bob

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

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## #5 2017-12-11 22:50:06

Jai Ganesh
Registered: 2005-06-28
Posts: 47,158

### Re: Correct Answer to 12 Days of Christmas Puzzle

Hi,

It's from the MIF puzzles:

Thank you, bob bundy!

It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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## #6 2017-12-13 21:32:55

Bob
Registered: 2010-06-20
Posts: 10,507

### Re: Correct Answer to 12 Days of Christmas Puzzle

And one more thing:

On the third day of Christmas (27th December and so on) my true love sent to me SIX presents:

. Three French hens
. Two turtle doves
. A partridge in a pear tree

The wording does make it clear what constitutes a 'present'.

Bob

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

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## #7 2018-07-13 03:13:09

elviraroose
Member
Registered: 2018-07-13
Posts: 1

### Re: Correct Answer to 12 Days of Christmas Puzzle

Should we choose only one answer, right? The thread contains a lot of ideas, but I don't even know which one is correct.