00:01
So here's problem 52, and i'm going to read it.
00:04
It says a bag contains one green marble, one red marble, and one blue marble.
00:18
And then we've got a diagram that shows the possible outcomes of randomly drawing three marbles from the bag without replacement.
00:23
And it says how many combinations of three marbles can be drawn from the bag? so we'll answer that part first is about the combinations.
00:36
And the key thing here about a combination is that the order doesn't matter.
00:52
So it doesn't matter if i pick the red marble first, the blue marble first, the green marble first, it's the same thing.
00:59
So if i want to draw three marbles from this group of three, there's only one way to do that because i'm picking all of the marbles and i don't care what order i'm sort of doing that in.
01:15
So there's only one combination.
01:19
And sometimes we write this situation as there's a set of three marbles and we are choosing three of them.
01:30
So that value is equal to one.
01:32
Three choose three is how you say that...