Answer
(a) 260000 possible license plates per country
(b) 23920000 license plates
Work Step by Step
We first need to find the possible combinations for the last 5 digits of the 7 digit license plate.
There are 26 choices for the 3rd digit (letter).
There are 10 choices for the 4th digit (number).
There are 10 choices for the 5th digit (number).
There are 10 choices for the 6th digit (number).
There are 10 choices for the 7th digit (number).
Thus there are:
26*10*10*10*10= 260000 possible license plates per country
(b)
Multiply the result we got from (a) by 92 (92 countries):
$260000 \times 92$
=23920000 license plates
