Hexadecimal digits are 0, 1, 2, 3, 4,
5, 6, 7, 8, 9, A, B, C, D, E, and F.
How many hexadecimal strings of length twelve have five A’s and
five B’s?
How many hexadecimal strings of length twelve have at most
three E’s?
How many hexadecimal strings of length twelve have exactly
three A’s and at least two B’s?
How many hexadecimal strings of length twelve have exactly two
A’s and exactly two B’s, so that the two...