• Re: Three rational triples

    From Keith F. Lynch@21:1/5 to Phil Carmody on Sun Oct 6 22:51:13 2024
    Phil Carmody <pc+usenet@asdf.org> wrote:
    "Keith F. Lynch" <kfl@KeithLynch.net> writes:
    HenHanna <HenHanna@dev.null> wrote:
    Keith F. Lynch wrote:
    Each of them has a sum that's equal to its product and is an integer.

    They're literally everywhere. Given 2 rational numbers, there's a solution

    (Here I've capped numerators and denominators to 50.)

    You missed the "and is an integer" part.

    I'm particularly enamoured with this find:
    4/3 7/6 9/2 7=7

    As well you might, since that was the only solution that met my
    criteria. But of course it was one of the solutions I listed
    in the first place.

    Again, I wish you luck in finding one that I didn't list.
    Even though there are infinitely many such.
    --
    Keith F. Lynch - http://keithlynch.net/
    Please see http://keithlynch.net/email.html before emailing me.

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  • From David Entwistle@21:1/5 to All on Mon Sep 16 19:10:45 2024
    On Wed, 11 Sep 2024 12:15:12 -0000 (UTC), Keith F. Lynch wrote:

    49/15, 25/21, 54/35

    --
    David Entwistle

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  • From David Entwistle@21:1/5 to Keith F. Lynch on Mon Sep 16 19:38:36 2024
    On Wed, 11 Sep 2024 12:15:12 -0000 (UTC), Keith F. Lynch wrote:

    I discovered that these three sets of three positive rationals have an interesting property in common:

    52/39, 7/6, 9/2

    --
    David Entwistle

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  • From Phil Carmody@21:1/5 to Keith F. Lynch on Tue Oct 1 20:39:30 2024
    "Keith F. Lynch" <kfl@KeithLynch.net> writes:
    HenHanna <HenHanna@dev.null> wrote:
    Keith F. Lynch wrote:
    Since it's been more than a week, and nobody has figured it out:
    Each of them has a sum that's equal to its product and is an integer.

    i think one person said exactly that.

    Who and when? I didn't see any such post.

    Is it easy to find them?

    No, even though there are infinitely many. Try and find one I
    didn't list.

    Constraints: All three numbers must be positive, real, and rational,
    but not integers.

    They're literally everywhere. Given 2 rational numbers, there's a solution

    (Here I've capped numerators and denominators to 50.)

    $ echo 'for(n=1,10000,a=(1+random(49))/(2+random(48));if(denominator(a)==1,next);b=1/a+(1+random(50))/(2+random(50));if(denominator(b)==1||numerator(b)>=50,next);x=(a+b)/(a*b-1);if(denominator(x)>1&&numerator(x)<50&&denominator(x)<50,print(a" "b" "x" "a+
    b+x"="a*b*x)))' | gp -q > crap
    $ sort -n crap | uniq
    1/2 11/4 26/3 143/12=143/12
    1/2 16/5 37/6 148/15=148/15
    1/2 19/8 46/3 437/24=437/24
    1/2 26/3 11/4 143/12=143/12
    1/2 29/7 13/3 377/42=377/42
    1/2 8/3 19/2 38/3=38/3
    1/3 21/5 34/3 238/15=238/15
    1/3 25/7 41/2 1025/42=1025/42
    1/3 31/5 49/8 1519/120=1519/120
    1/3 36/7 23/3 92/7=92/7
    1/4 11/2 46/3 253/12=253/12
    2/3 11/2 37/16 407/48=407/48
    2/3 11/6 45/4 55/4=55/4
    2/3 7/2 25/8 175/24=175/24
    2/3 9/4 35/6 35/4=35/4
    2/5 7/2 39/4 273/20=273/20
    3/2 13/7 47/25 1833/350=1833/350
    3/2 17/3 43/45 731/90=731/90
    3/2 29/24 10/3 145/24=145/24
    3/2 3/2 12/5 27/5=27/5
    3/2 4/3 17/6 17/3=17/3
    3/2 5/3 19/9 95/18=95/18
    3/2 8/3 25/18 50/9=50/9
    3/4 19/3 17/9 323/36=323/36
    3/4 8/3 41/12 41/6=41/6
    3/5 11/3 32/9 352/45=352/45
    4/3 12/11 16/3 256/33=256/33
    4/3 13/2 47/46 611/69=611/69
    4/3 13/4 11/8 143/24=143/24
    4/3 17/6 3/2 17/3=17/3
    4/3 49/12 39/32 637/96=637/96
    4/3 7/4 37/16 259/48=259/48
    4/3 7/6 9/2 7=7
    4/3 9/4 43/24 43/8=43/8
    4/5 7/3 47/13 1316/195=1316/195
    5/2 7/5 39/25 273/50=273/50
    5/3 8/5 49/25 392/75=392/75
    6/5 3/2 27/8 243/40=243/40
    6/7 19/12 41/6 779/84=779/84
    6/7 9/2 15/8 405/56=405/56
    7/2 5/3 31/29 1085/174=1085/174
    7/3 9/7 38/21 38/7=38/7
    7/9 29/7 31/14 899/126=899/126
    8/5 3/2 31/14 186/35=186/35
    9/2 5/3 37/39 185/26=185/26
    15/7 3/5 48/5 432/35=432/35
    20/21 5/2 5/2 125/21=125/21
    22/7 10/11 24/11 480/77=480/77
    42/11 20/21 38/21 1520/231=1520/231

    I'm particularly enamoured with this find:
    4/3 7/6 9/2 7=7

    Widening the net, I was unable to find any other integer sum/products.
    Can anyone else find another one - I suspect actually using some algebra
    might make sense, rather than just probing randomly.

    Other small denominators are everywhere:

    1/12 63/4 152/3 133/2=133/2
    1/28 147/4 824/7 309/2=309/2
    1/3 9/2 29/3 29/2=29/2
    1/33 729/22 24079/3 16119/2=16119/2
    1/5 29/5 75/2 87/2=87/2
    1/7 49/2 69/7 69/2=69/2

    1/15 78/5 1175/3 1222/3=1222/3
    1/18 172/9 621/2 989/3=989/3
    1/2 16/3 7/2 28/3=28/3
    1/2 19/2 8/3 38/3=38/3
    1/2 7/2 16/3 28/3=28/3
    1/4 16/3 67/4 67/3=67/3
    1/4 19/4 80/3 95/3=95/3
    1/5 25/3 64/5 64/3=64/3
    1/5 64/5 25/3 64/3=64/3
    1/6 15/2 92/3 115/3=115/3
    1/6 20/3 123/2 205/3=205/3
    1/7 55/7 196/3 220/3=220/3
    1/78 169/2 13184/13 3296/3=3296/3
    1/8 103/8 64/3 103/3=103/3
    2/15 25/3 381/5 254/3=254/3
    2/7 26/7 196/3 208/3=208/3
    3/2 17/6 4/3 17/3=17/3
    3/2 28/3 5/6 35/3=35/3
    3/2 5/6 28/3 35/3=35/3
    4/3 3/2 17/6 17/3=17/3
    4/3 39/2 5/6 65/3=65/3
    4/3 5/6 39/2 65/3=65/3
    5/6 3/2 28/3 35/3=35/3
    5/6 4/3 39/2 65/3=65/3




    Phil
    --
    We are no longer hunters and nomads. No longer awed and frightened, as we have gained some understanding of the world in which we live. As such, we can cast aside childish remnants from the dawn of our civilization.
    -- NotSanguine on SoylentNews, after Eugen Weber in /The Western Tradition/

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  • From Keith F. Lynch@21:1/5 to All on Wed Sep 11 12:15:12 2024
    I discovered that these three sets of three positive rationals have an interesting property in common:

    9/2, 4/3, 7/6

    49/15, 25/21, 54/35

    49/2, 4/7, 27/14

    If nobody figures it out, I will provide the answer in a week.
    --
    Keith F. Lynch - http://keithlynch.net/
    Please see http://keithlynch.net/email.html before emailing me.

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  • From Keith F. Lynch@21:1/5 to Keith F. Lynch on Wed Sep 18 22:39:45 2024
    Keith F. Lynch <kfl@KeithLynch.net> wrote:
    I discovered that these three sets of three positive rationals have
    an interesting property in common:

    9/2, 4/3, 7/6
    49/15, 25/21, 54/35
    49/2, 4/7, 27/14

    If nobody figures it out, I will provide the answer in a week.

    Since it's been more than a week, and nobody has figured it out:

    Each of them has a sum that's equal to its product and is an integer.

    For instance 9/2 + 4/3 + 7/6 = 7 and 9/2 x 4/3 x 7/6 = 7.

    Here are some more triples with this same unusual property:

    121/42, 637/66, 36/77
    81/5, 50/9, 11/45
    625/18, 81/50, 148/225
    289/15, 950/51, 9/85
    49/3, 207/7, 2/21
    450/13, 169/15, 23/195
    25/2, 252/5, 1/10
    81/2, 292/9, 1/18
    242/5, 325/11, 3/55
    121/2, 92/11, 3/22
    625/21, 4214/75, 81/1575
    676/7, 49/26, 99/182
    245/3, 198/7, 1/21
    343/3, 81/7, 2/21
    578/5, 175/17, 9/85
    529/3, 126/23, 13/69
    289/2, 756/17, 1/34
    525/2, 52/5, 1/10
    --
    Keith F. Lynch - http://keithlynch.net/
    Please see http://keithlynch.net/email.html before emailing me.

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  • From HenHanna@21:1/5 to Keith F. Lynch on Thu Sep 19 02:39:59 2024
    On Wed, 18 Sep 2024 22:39:45 +0000, Keith F. Lynch wrote:

    Keith F. Lynch <kfl@KeithLynch.net> wrote:
    I discovered that these three sets of three positive rationals have
    an interesting property in common:

    9/2, 4/3, 7/6
    49/15, 25/21, 54/35
    49/2, 4/7, 27/14

    If nobody figures it out, I will provide the answer in a week.

    Since it's been more than a week, and nobody has figured it out:

    Each of them has a sum that's equal to its product and is an integer.


    i think one person said exactly that.


    Is it easy to find them?



    How about 2 numbers

    2+2 = 2*2

    1+x = 1*x ------- No sol.

    3+x = 3*x ------- easy to solve.

    A+x = A*x ------- all easy to solve.









    For instance 9/2 + 4/3 + 7/6 = 7 and 9/2 x 4/3 x 7/6 = 7.

    Here are some more triples with this same unusual property:

    121/42, 637/66, 36/77
    81/5, 50/9, 11/45
    625/18, 81/50, 148/225
    289/15, 950/51, 9/85
    49/3, 207/7, 2/21
    450/13, 169/15, 23/195
    25/2, 252/5, 1/10
    81/2, 292/9, 1/18
    242/5, 325/11, 3/55
    121/2, 92/11, 3/22
    625/21, 4214/75, 81/1575
    676/7, 49/26, 99/182
    245/3, 198/7, 1/21
    343/3, 81/7, 2/21
    578/5, 175/17, 9/85
    529/3, 126/23, 13/69
    289/2, 756/17, 1/34
    525/2, 52/5, 1/10

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  • From HenHanna@21:1/5 to Keith F. Lynch on Thu Sep 12 19:19:31 2024
    XPost: sci.lang

    On 9/11/2024 5:15 AM, Keith F. Lynch wrote:
    I discovered that these three sets of three positive rationals have an interesting property in common:

    9/2, 4/3, 7/6

    49/15, 25/21, 54/35

    49/2, 4/7, 27/14

    If nobody figures it out, I will provide the answer in a week.



    that sounds good.

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  • From Ammammata@21:1/5 to Keith F. Lynch used his keyboard to on Fri Sep 13 11:37:47 2024
    Keith F. Lynch used his keyboard to write :
    I discovered that these three sets of three positive rationals have an interesting property in common:

    9/2, 4/3, 7/6

    49/15, 25/21, 54/35

    49/2, 4/7, 27/14

    If nobody figures it out, I will provide the answer in a week.

    normalizing to lowest common denominator I get

    27/6 8/6 7/6
    343/105 125/105 162/105
    343/14 8/14 27/14

    where the numerator of first and second is a cube and the third is not
    :-)

    --
    /-\ /\/\ /\/\ /-\ /\/\ /\/\ /-\ T /-\
    -=- -=- -=- -=- -=- -=- -=- -=- - -=-
    ........... [ al lavoro ] ...........

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  • From Keith F. Lynch@21:1/5 to HenHanna on Thu Sep 19 12:16:57 2024
    HenHanna <HenHanna@dev.null> wrote:
    Keith F. Lynch wrote:
    Since it's been more than a week, and nobody has figured it out:
    Each of them has a sum that's equal to its product and is an integer.

    i think one person said exactly that.

    Who and when? I didn't see any such post.

    Is it easy to find them?

    No, even though there are infinitely many. Try and find one I
    didn't list.

    Constraints: All three numbers must be positive, real, and rational,
    but not integers.

    And of course have to be in simplest form, i.e. 1/2, not 2/4. One
    person posted "52/39, 7/6, 9/2" which is of course the same three
    numbers as my "9/2, 4/3, 7/6". And he didn't say what property
    they had, anyway.

    Without any constraints, x,i,-i is always a solution for any x,
    if i is the square root of minus one.

    How about 2 numbers

    Too simple to be interesting. If you want two numbers to have a sum
    of S and a product of P, whether or not S=P, the two numbers will be
    S + sqrt(S^2 - 4P) and S - sqrt(S^2 - 4P).
    --
    Keith F. Lynch - http://keithlynch.net/
    Please see http://keithlynch.net/email.html before emailing me.

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  • From HenHanna@21:1/5 to IlanMayer on Thu Sep 19 17:11:53 2024
    XPost: sci.lang

    Keith F. Lynch wrote:
    Since it's been more than a week, and nobody has figured it out:
    Each of them has a sum that's equal to its product and is an integer.

    i think one person said exactly that.


    ----------- Who and when? I didn't see any such post.


    So this post below didn't get to your site (or Newsreader).




    On Fri, 13 Sep 2024 12:58:08 +0000, IlanMayer wrote:

    On Fri, 13 Sep 2024 2:19:31 +0000, HenHanna wrote:

    On 9/11/2024 5:15 AM, Keith F. Lynch wrote:
    I discovered that these three sets of three positive rationals have an
    interesting property in common:

    9/2, 4/3, 7/6

    49/15, 25/21, 54/35

    49/2, 4/7, 27/14

    If nobody figures it out, I will provide the answer in a week.



    that sounds good.


    SPOILER
































    The sum of each triplet is the same as its product.

    9/2*4/3*7/6 = 9/2+4/3+7/6 = 7
    49/15*25/21*54/35 = 49/15+25/21+54/35 = 6
    49/2*4/7*27/14 = 49/2+4/7+27/14 = 27

    Please reply to ilanlmayer at gmail dot com

    __/\__
    \ /
    __/\\ //\__ Ilan Mayer
    \ /
    /__ __\ Toronto, Canada
    /__ __\
    ||

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  • From IlanMayer@21:1/5 to HenHanna on Fri Sep 13 12:58:08 2024
    XPost: sci.lang

    On Fri, 13 Sep 2024 2:19:31 +0000, HenHanna wrote:

    On 9/11/2024 5:15 AM, Keith F. Lynch wrote:
    I discovered that these three sets of three positive rationals have an
    interesting property in common:

    9/2, 4/3, 7/6

    49/15, 25/21, 54/35

    49/2, 4/7, 27/14

    If nobody figures it out, I will provide the answer in a week.



    that sounds good.


    SPOILER
































    The sum of each triplet is the same as its product.

    9/2*4/3*7/6 = 9/2+4/3+7/6 = 7
    49/15*25/21*54/35 = 49/15+25/21+54/35 = 6
    49/2*4/7*27/14 = 49/2+4/7+27/14 = 27

    Please reply to ilanlmayer at gmail dot com

    __/\__
    \ /
    __/\\ //\__ Ilan Mayer
    \ /
    /__ __\ Toronto, Canada
    /__ __\
    ||

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  • From Keith F. Lynch@21:1/5 to HenHanna on Fri Sep 20 00:07:29 2024
    XPost: sci.lang

    HenHanna <HenHanna@dev.null> wrote:
    So this post below didn't get to your site (or Newsreader).
    IlanMayer wrote:
    . . .
    The sum of each triplet is the same as its product.

    9/2*4/3*7/6 = 9/2+4/3+7/6 = 7
    49/15*25/21*54/35 = 49/15+25/21+54/35 = 6
    49/2*4/7*27/14 = 49/2+4/7+27/14 = 27

    Please reply to ilanlmayer at gmail dot com

    __/\__
    \ /
    __/\\ //\__ Ilan Mayer
    \ /
    /__ __\ Toronto, Canada
    /__ __\
    ||

    Thanks for forwarding that. I don't know why that post never showed
    up on Panix.
    --
    Keith F. Lynch - http://keithlynch.net/
    Please see http://keithlynch.net/email.html before emailing me.

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  • From guido wugi@21:1/5 to All on Fri Sep 13 22:30:47 2024
    XPost: sci.lang

    Op 13-9-2024 om 04:19 schreef HenHanna:
    On 9/11/2024 5:15 AM, Keith F. Lynch wrote:
    I discovered that these three sets of three positive rationals have an
    interesting property in common:

    9/2, 4/3, 7/6

    49/15, 25/21, 54/35

    49/2, 4/7, 27/14

    If nobody figures it out, I will provide the answer in a week.



            that sounds good.

    They are three, they are positive, they are rationals, they're written
    in the same form and the same number base or whatsitcalled, they are
    mentioned here (and no others are).
    Anything else yet?

    --
    guido wugi :o)

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