Question

Evaluate 7C2. Explain how you got your answer.

Answer 1

So, to evaluate a combination, there's a formula we use.

I don't remember the formula from the top of my head, lol, but this is how you solve them.

7 c 2

When doing combinations and permutations each number is always in a factorial. We always start with the number on the left.

7! That's the total amount. The number on the left divides into that.

7! / 2!

We're not done yet. Here's the tricky part. We also always divide the number on the left, in this case 7!, with the positive difference of both numbers given to us.

7 - 2 = 5

So, we have 7! / 5! / 2! = 21.

Hope that helped!

Let's work another one.
5 c 3

We have 5! / 3! ,but we need to also divide 5! by the positive difference of 5 and 3. We get 2.

So, 5! / 3! / 2! = 10.

If you have any questions then leave a comment. Good luck!