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looking for a math formula

Topic closed. 8 replies. Last post 9 years ago by RJOh.

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regy's avatar - scenery water_mountains.jpg
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Montreal
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Posted: October 13, 2007, 8:40 pm - IP Logged

Do someone know the formula to calculate how many X combination in Y !

For example lets say i wanna know how many 20 numbers combination bettween 1 and 70 !

    time*treat's avatar - radar

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    Posted: October 13, 2007, 9:21 pm - IP Logged

    To calculate the number of combinations of n elements taken r at a time.

    n C r = n! / [(n-r)! * r!]

    70 C 20 = 70! / [(70-20)! * 20!]

                    = 70! / [50! * 20!]

                      = 1.6188 e 17

      RJOh's avatar - chipmunk
      mid-Ohio
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      Posted: October 13, 2007, 9:25 pm - IP Logged

       C(20,70) = 1.618846036626579D+17  It's approximately 161,884,603,662,658,000.  You use the same formula that you use to calculate the number of smaller combinations within a pool of numbers but you will get the scientific notation when using your computer if the program can't handle more than 16 digits. 

      You might get more accuracy if you used a program designed to calculate keno odds or a scientific calculator.

       * you don't need to buy more tickets, just buy a winning ticket * 
         
                   Evil Looking       

        regy's avatar - scenery water_mountains.jpg
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        Posted: October 13, 2007, 9:43 pm - IP Logged

        Wow ! Thank for the fast response guy's Smile

          Avatar
          NY
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          Posted: October 13, 2007, 9:56 pm - IP Logged

          Even easier:

          http://www.wiley.com/college/mat/gilbert139343/java/java05_applet.html

            time*treat's avatar - radar

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            Posted: October 14, 2007, 12:31 am - IP Logged

            nice little app, but it seems to not like numbers this big.

            closest you can get are 70C18 and 80C16 

              johnph77's avatar - avatar
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              Posted: October 14, 2007, 9:38 am - IP Logged

              http://www.johnph77.com/math/kenocomp.html

              No ads, nothing to sell, for informational purposes only.

              gl

              j

              Blessed Saint Leibowitz, keep 'em dreamin' down there..... 

              Next week's convention for Psychics and Prognosticators has been cancelled due to unforeseen circumstances.

               =^.^=

                regy's avatar - scenery water_mountains.jpg
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                Posted: October 14, 2007, 10:41 pm - IP Logged

                http://www.johnph77.com/math/kenocomp.html

                No ads, nothing to sell, for informational purposes only.

                gl

                j

                All the info i was looking for is there !

                 Thanks for the link ! Thumbs Up

                  RJOh's avatar - chipmunk
                  mid-Ohio
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                  Posted: October 15, 2007, 4:40 pm - IP Logged

                  I stand corrected, when you use the scientific version of the calculator that comes in Windows to calculate 70!/(50! * 20!) the answer is not in scientific notation 1.618846036626579D+17 but in whole numbers 161884603662657876.

                   * you don't need to buy more tickets, just buy a winning ticket * 
                     
                               Evil Looking