Base on the question the license plate should have 6 number. The first 3 letters are letters which can be from A to Z. Possible letters altogether are 26 in number. The last 3 characters must be numbers which can be 0 to 9 . The possible numbers are 10 digits.
You didn't indicate whether the letters can be repreated or the numbers can be reppeated .
If the numbers and letter can be repreated .



Now if the letters and numbers can be repeated.

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