License plates are made using 2 letters followed by 3 digits. how many plates can be made if repetition of letters and digits is allowed?

number of possible combinations = 676000

Explanation:
We have:
26 possible letters (a to z)
10 possible digits(0 to 9)
2 letters followed by 3 digits

For letters, since repetition is allowed, therefore, each of the two letters can be any of the possible 26 alphabetical letters (a to z)
For digits, since repetition is allowed, therefore, each digit of the three can be any of the possible 10 digits (0 to 9)

Therefore:
number of combinations = letter * letter * digit * digit * digit
number of combinations = 26 * 26 * 10 * 10 * 10
number of possible combinations = 676000

Hope this helps :)