00:01
Hi, i'm david and i'm here to help you answer your question.
00:04
Now let me bring up your question here.
00:06
Here a bag contains 80 bones numbered from 1 to 80.
00:11
Before the game starts, we choose 10 different numbers from amongst 1 to 80 and write them down on the piece of paper.
00:20
So let me try to summarize the question here.
00:23
We will have total of 80 bones and inside the 80 bones that will be the 10 that will be the one you wrote down so i just say that 10 yards and we put as a y here and then the orders will be the 70 that will be the order i will be the o and we put this one will be some i will put the piece then for the bones now we will choose select 20 bones without replacement and in the question a 1.
01:03
Once you find the probability that all your numbers are selected, it means that will be 10 y here.
01:10
This one just equal to the proportion, where the denominator will be the number of the ways, we can choose 20 bones out of the 80 bones.
01:19
And that's just equal to the combination.
01:22
Combination here will be the 80, we will choose 20.
01:26
Now for the numerator, it will be that from the group of the 10y.
01:32
And then we will choose all of them.
01:36
And then from the group of the seven or the bones, we will choose zero of them.
01:42
And then we get the answer will be the one divided by the 80, choose 20.
01:50
So this one very small value here, so we will just equal to the 1 divided 80 over 20.
01:58
Equal to the 80, we choose 20.
02:02
And that's going to be the answer for this question.
02:05
Now for the b, once you find the probability that none of your numbers is selected.
02:12
So we'll be on, this one will be that we choose 20.
02:17
Sorry about that.
02:18
So we want to choose 20...