Question

In how many ways can you select two people from a group of 15 if the order of selection is not important?

Answer 1

105 ways, because the order of selection does not matter, we know that we will be using a combination instead of a permutation.

Answer 2

105 ways

Explanation:

Because the order of selection does not matter, we know that we will be using a combination instead of a permutation.

₁₅C₂ = 15! / (2! * 13!)

= 15 * 14 * ... * 2 * 1 / 2 * 1 * 13 * 12 * ... * 2 * 1

= 15 * 14 / 2 * 1 (The 13! cancels out)

= 105