00:01
All right, in your question, you're asked to determine how many possible zip codes there are.
00:05
That's the five -digit version.
00:07
How many possible plus four zip codes, the four numbers at the end? and then how many total possibilities if we include all nine numbers? so for the first five -digit zip code, i have five digits to choose from here.
00:23
The first four digits, it says, can be anything from zero to nine.
00:32
But the last digit can only be from 1 to 8.
00:37
Okay, there are 10 numbers from 0 to 9, so that means we could choose any of the 10 for those numbers.
00:45
There would only be 8 numbers from 1 to 8.
00:48
Now to get the total possible outcomes, we simply multiply those values.
00:55
So 10, i can just do 10 to the 4th power times 8, and that works out to be 80 ,000 zip codes.
01:08
Now the plus 4 zip code has restrictions on the numbers.
01:13
It says the first three digits can be anything 0 to 9, which would be 10, 10, 10.
01:22
The last one can be 1 to 9, and that would be 9 numbers.
01:27
Again, we just multiply those out.
01:31
So i'm doing 10 to the third power times 9.
01:36
And we end up with 9 ,000.
01:40
Now, for the total possibilities, basically we just put this whole group together with this whole group and we just keep multiplying.
01:50
Or i could take the results and multiply them, which is the quicker way to do it...