Question

A license plate consists of three letters followed by three numbers
a. how many of those license plates are possible?
b. how many plates are possible if repetition is not allowed?

Answer 1

For option a:
For the three letters the permutations would be 26 x 26 x 26 and for the numbers it would be 10 x 10 x 10. So the answer would be 26 x 26 x 26 x 10 x 10 x 10.

Answer 2

For option b:
For the letters the permutations would be 26 x 25 x 24(no repetitions) and for the numbers it would be 10 x 9 x 8.