Two Card Draw

Standard memberRemoved
Posers and Puzzles 13 Apr '21 23:48
  1. R
    Standard memberRemoved
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    13 Apr '21 23:482 edits
    You have the following cards to choose from:

    A,2,3,4,5,6,7,8,9,10

    If you draw two cards at random ( without replacement ) does the sum of there face values have a higher probability of being even or odd?

    The "A" has a value of 1
  2. Standard memberBigDogg
    Secret RHP coder
    on the payroll
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    14 Apr '21 02:32
    @joe-shmo

    10 ways to draw the first card
     5 evens
      9 ways to draw the 2nd card
       5 odds
       4 evens
     5 odds
      9 ways to draw the 2nd card
       5 evens
       4 odds

    cases tally, resultant sum parity
     25 e-o, o
     20 e-e, e
     25 o-e, o
     20 o-o, e

    5/9 chance of being odd
    4/9 chance of being even

    P.S. I feel like an RHP god, getting my text to indent like that.
  3. R
    Standard memberRemoved
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    14 Apr '21 13:47
    @bigdoggproblem said
    @joe-shmo

    10 ways to draw the first card
     5 evens
      9 ways to draw the 2nd card
       5 odds
       4 evens
     5 odds
      9 ways to draw the 2nd card
       5 evens
       4 odds

    cases tally, resultant sum parity
     25 e-o, o
     20 e-e, e
     25 o-e, o
     20 o-o, e

    5/9 chance of being odd
    4/9 chance of being even

    P.S. I feel like an RHP god, getting my text to indent like that.
    Correct!

    There are C(10,2) = 45 ways to draw two cards

    The sum is even if they have the same parity:

    Both even:
    C( 5,2) = 10 ways
    Both odd:
    C( 5,2) = 10 ways

    20 ways

    The sum is odd if thy have opposite parity

    5*5 = 25 Ways

    P( even sum ) = 20/45 = 4/9

    and

    P( odd sum ) = 25/45 = 5/9

    P.S. The reply/quote reveals none of your magic for indenting the text! Are you willing to share this valuable information, or are we "lesser's" left to marvel at your greatness?
  4. Standard memberBigDogg
    Secret RHP coder
    on the payroll
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    14 Apr '21 17:08
    @joe-shmo

    I found the site:
    https://emptycharacter.com/

    I copied the Em Space from the Unicode Empty Characters section.
  5. R
    Standard memberRemoved
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    14 Apr '21 17:319 edits
    This is a
     test

    Good find! Thanks BDP

    Σ ⟷ ∫ ⬂ ↺ ℕ  🂸

    You've inspired me to look for more symbols that copy/paste from unicode. This should make some math a little more readable.

    https://www.vertex42.com/ExcelTips/unicode-symbols.html
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