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Homework Help: Discrete Math - Counting Theory

  1. Jul 25, 2004 #1
    Hexadecimal numbers are made using the sixteen digits 0 - 9, A-F. how many hexadecimal numbers are there between the hexadecimal numbers 30 and AF?

    There are 8 numbers between 3 and A, so I got 3 x 16, but I don't really know.
     
  2. jcsd
  3. Jul 25, 2004 #2
    Try converting AF to a base 10 number.

    How many numbers are between 30 and this number?
     
  4. Jul 25, 2004 #3
    30 = 48
    AF = 175

    126 numbers between

    However, the example in the book is 50 and FF and the solution is, 5 and F is 11 numbers away. There are 16 hexadecimal numbers, so there are 11 x 16 hexadecimal numbers.
    50 = 80
    FF = 255
    That comes out to be 174 numbers. That's not 11 x 16.
     
  5. Jul 25, 2004 #4
    176 includes 50 and FF. 174 excludes 50 and FF.
    128 inculdes 30 and AF. 126 excludes 30 and AF. (In your original post you said 3x16, I think you meant 8x16. Also, thanks for catching my mistake, I forgot that 30 was also a hexidecimal number.)
     
    Last edited: Jul 25, 2004
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