Answer:
6
Step-by-step explanation:
6 is a multiple of three with only itself
Answer:
8
Step-by-step explanation:
Answer:
14 square units
Step-by-step explanation:
The number of permutations of the 25 letters taken 2 at a time (with repetitions) is:

The number of permutations of the 9 digits taken 4 at a time (with repetitions) is:

Each permutation of letters can be taken with each permutation of digits, therefore the total number of possible passwords is: