We will see that the number of different combinations for each case are:
We have 5 selections for each password, we need to find the number of options for each one of these selections.
a) Here we can use only capitals an we can repeat, so for each selection (each letter), we have 26 options.
The total number of combinations will be equal to the product between the numbers of options:
C = 26*26*26*26*26 = 11,881,376
b)Now we can use either capitals or lower case, but we can't repeat. (Here I assume that A is different than a, so we can't use A two times, but we could use A and a).
Then we have 26*2 = 52 options.
For the first letter, we have 52 options.
For the second letter, we have 51 options (because one letter was already used).
For the third letter, we have 50 options, and so on.
The total number of combinations will be:
C = 52*51*50*49*48 = 311,875,200
If you want to learn more about combinations, you can read:
https://brainly.com/question/251701