troubleshooting Question

Probability problem

Avatar of Ed Covney
Ed CovneyFlag for United States of America asked on
Math / Science
21 Comments1 Solution294 ViewsLast Modified:
This "Probability" problem has stumped me for several weeks:

If I randomly select a 20 character password from a set of 256 characters composed of:
   4 sets of lower case letters (104),
   3 sets of Upper case letters  (78),
   7 of each number in 0..5      (42) and
   8 of each number in 6..9      (32)
                        total   (256)

What are the chances a second random 20 character selection will match the first?

  P(M,N) means the probability of M items taken N at a time, order counts.
  C(M,N) means the # of combinations of M items taken N at a time (order is n/a)

Many thanks . . .

- Ed
Research Engineer - Electrical

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