00:01
In a certain state, license plates have three letters followed by three digits.
00:05
We want to know how many plates are possible if we allow repetition, if we don't allow repetition.
00:12
Okay, so part a, we allow repetition.
00:15
So there are 26 letters they might use.
00:17
There are 10 digits.
00:22
26 letters, 10 digits.
00:25
Now, if we have repetition, how many options do i have for the first letter in the plate? well, 26, any of them.
00:32
What about the second? also 26.
00:35
I can reuse the first letter if i want to.
00:38
And so on.
00:39
So we have 26 multiplied by itself three times, or the letters.
00:44
Digits, it doesn't tell us if they should be repeated or not...