00:01
Hi, i'm david and i'm here to help you answer your question.
00:03
Now let me bring up your question here.
00:06
In the question here, let me try to summarize the question by the diagram.
00:11
Now we have a bag.
00:13
Back it will contain the eight red marbles, and then seven white, and then we have the five blue.
00:25
And we're going to draw the three marbles without replacement.
00:33
And notice that the total here, it will equal to the 20 marbles.
00:41
Now in the question i ask you to find the probability that on the marble as red, so we'll be on three red.
00:53
So it just means that we will have three red and then zero white and then the zero blue as well.
01:02
So we will have this one just equal to the proportion.
01:06
The denominator will be the total number.
01:08
Number of the ways we will choose three marbles out of the 20 marbles and it's equal to the combination so we have from 20 we will choose three and from the set of the eight red we choose three red so we'll be from eight we choose three from the set of the seven white we will choose zero white seven white i choose zero from the set of the five blue i will choose zero blue so if we compute this one that equal to a2 .3 divided 223, equal to the 0491.
01:48
Around to the four decimal places.
01:50
Now for the question b, once you find the probability that exactly two of the marble is red.
01:56
So we have the two red and then the orders will be one orders...