16. Counting Flashcards
1
Q
Multiplication Principle
(rule of product)
A
If there are a ways of doing something and b ways of doing another thing, then there are a • b ways of performing both actions.
2
Q
Factorials used in counting
A
The number of ways “n” objects can be ordered is n!
3
Q
Relationship between Permutations and Combinations
A
A Permutation is an ordered combiation.
4
Q
Permutation
Formula
A
A set of objects in which position (or order) is important.
nPr = n! / (n – r)!
5
Q
Combination
Formula
A
A set of objects in which position (or order) is not important.
nCr = n! / (n – r)! r!
6
Q
A
The number of ways r objects can be chosen from n.
