From the course: Test Prep: GRE

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Combinations

Combinations

From the course: Test Prep: GRE

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Combinations

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- [Voiceover] Combinations in order doesn't matter. So I'll start off with the language for this. It's a lot of times, gonna be things like, groups, we're gonna be talking about how many groups can we make or how many sets can we make or subsets, maybe. Subsets, I'll give you an example of this. Let's say we have a group of eight people, and we want to see how many groups of three can we make out of that total group of eight. So let's say how many groups of three? Okay, so you should know something about a group. Let's say I have a group. Let's say these people are people A, B, C, D, E, F, G,and H. Let's say those are our people. Notice that the group, A, B, C, and C, B, A are really the same group. We don't want to double count them. So we need a formula here, formula for combinations, and I'll show you the way that I like to teach it. It's gonna be the big number factorial over the little number factorial, times the big number minus the little number factorial. I like to use big and…

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