So I had my first class today (studying SE), which was Computer Networks. At the end of the lecture, the teacher posed a few exercises, which looks nothing like what I had, when I did my marine engineering degree. I can see the logic in the exercises, but I was wondering which branch of math this is, so I can study it more closely, since I have a feeling I will be seeing a lot of it.
A few examples:
Suppose you have forgotten a password with 5 characters.
You only remember:
➢ the 5 characters are all distinct
➢ the 5 characters are B, D, M, P, Y
If you want to try all possible combinations, how many of them in total?
What if the password is in the form adaaada?
➢ a means letter, d means digit
➢ all characters are all distinct
➢ the 5 letters are B, D, M, P, Y
➢ the digit is either 0 or 1
How many combinations are there?
What if the password is in the form adaaada?
➢ a means letter, d means digit
➢ all characters are all distinct
➢ the 5 letters from B, D, M, P, Y, Z, W
➢ If B appears in the password, D will not be allowed to appear
➢ the digit is either 0 or 1
How many combinations are there?
A few examples:
Suppose you have forgotten a password with 5 characters.
You only remember:
➢ the 5 characters are all distinct
➢ the 5 characters are B, D, M, P, Y
If you want to try all possible combinations, how many of them in total?
What if the password is in the form adaaada?
➢ a means letter, d means digit
➢ all characters are all distinct
➢ the 5 letters are B, D, M, P, Y
➢ the digit is either 0 or 1
How many combinations are there?
What if the password is in the form adaaada?
➢ a means letter, d means digit
➢ all characters are all distinct
➢ the 5 letters from B, D, M, P, Y, Z, W
➢ If B appears in the password, D will not be allowed to appear
➢ the digit is either 0 or 1
How many combinations are there?