How many different arrangements of 5 letters can be formed if the first letter must be W or K (repeats of letters are allowed)?

There are ___ different 5-letter combinations that can be formed.

(Simplify your answer.)

How many different arrangements of 5 letters can be formed if the first letter must be W or K (repeats of letters are allowed)?

There are ___ different 5-letter combinations that can be formed.

(Simplify your answer.)