00:01
So for part a, we can pick among the 26 letters and the number is 0 through 9.
00:10
So that's going to be 10 numbers.
00:14
And if we have no restrictions, that means that we could have like the same letter five times as one of our possibilities.
00:21
So basically there's 36 different things, 26 plus 10, that you could pick each time and you want five characters.
00:30
So we're just going to take 36 to the fifth power.
00:33
36 ways for the first, 36 ways for a second, and so on.
00:37
And then when we take that, we get a very large number.
00:48
60 ,000, 176 ,000, 176 different weights.
00:55
If there was like a restriction that you had to, you couldn't use the same letter number twice, then it would be like 36 times 75 times 34 and so all.
01:05
All right, for part b, the characters have to alternate between letters and numbers.
01:12
So we could, if we assume that we start with a letter, there's 26 ways to pick the first one...