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April 29, 2016
Posted by **Randy** on Wednesday, May 23, 2012 at 5:53pm.

- ALGEBRA -
**MathMate**, Wednesday, May 23, 2012 at 9:54pmSo the template is

NXXNNNN

I interpret the "repeated digit" as any two identical digits appearing anywhere on the licence plate, as opposed to two identical digits next to each other.

Also, it was not specified as "exactly one repeated letter or digit", so we assume multiple repetitions are acceptable, such as 5AA5002, or 4BB3344, etc.

First, we find the size of the sample space (Ω)

N=|Ω| = 10*26*26*10*10*10*10

=67,600,000

It is easier to find the number of licence plates that have distinct digits and letters, namely:

n=10*26*25*9*8*7*6=19,656,000

Therefore, number of licence plates with at least one repeated digit or letters is

67,600,000-19,656,000

=47,944,000