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Finding probablity example 3

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Find the probability of pulling a yellow marble from a bag with three yellow, two red, two green, and one blue marbles, I'm assuming. So let's just think about this bag a little bit. There are three yellow marbles in it. So let me draw them. We have one, two, three yellow marbles. We have two red marbles. So we have one, two red marbles, assuming they're all mixed in there. We have two green marbles-- one, two green marbles. And then there's one blue marble. And they want to know the probability of pulling a yellow marble. So they want to know what is the probability of pulling a yellow marble. Now probability is just a way of expressing-- well, I don't want to use too loaded words. But it's the odds of picking yours relative to the odds of picking everything else. Or another way of thinking about it is, it's the number of outcomes that could result in what you want, a yellow marble, over the total number of outcomes. So how many ways are there-- how many events-- you're going to pick out a ball. How many of those-- how many ways-- or how many balls can you pick out that will be yellow? Well, there's three balls. There's three balls that you can pick out as yellow. One, two, and three. We're assuming that they're all equally likely to be picked up. They're all mixed in there. So there's three yellow balls you could pick up. Now how many total balls are there? How many total balls are there to be picked up? Well, you could be picking up any one of eight balls, right? One, two, three, four, five, six, seven, eight. So there's a total number of eight balls. So the probability of picking a yellow marble is 3/8. So you have a 3/8 chance of picking a yellow marble. And just a way to think about it. I just want to reiterate. It's just the number of outcomes. There's eight total outcomes. There's eight different things that you could pull out of the bag. Three of them satisfy your conditions. Three of them would be a yellow marble.