Asked by Diana

how many 4 character license plates are possible with 2 letters of the alphabet followed by 2 digits, it repetitions are allowed?

if repetitions are not allowed?
Answered by MathMate
Assuming all 26 letters are used, there is a choice of 25 letters for the first character, 26 for the second, 10 for the third, and 9 for the fourth.
The total number is the product of the four numbers.
Answered by MathMate
If repetitions are allowed, the choies are 26,26,10,10.