8-2:Permutations and 8-2:Permutations and CombinationsCombinations

8-2:Permutations and 8-2:Permutations and CombinationsCombinations

English CasbarroEnglish CasbarroUnit 8Unit 8

A permutation is all possible arrangements of people or things where order is important.

A linear permutation is the arrangement of people or objects in a line.

Permutations with repetition

Ex. In how many ways can you arrange the letters in geometry?

For our first example, we had the following problem.

Suppose it had said instead: “Ten students are in a race. The top three willmove on to the finals”. Does it matter now which is first, which is second,

or which is third? In this situation, you use a combination.

Ten students are in a race. The top three will move on to the finals. How many ways can this happen?

Order is not important here– so you would use combinations. It is written 10C3.

Deciding whether order is important

and arrange the

four drawings from left to right on the wall?