Math Test Chapter 15

Counting Principle

# in A and B = #A + #B - # in intersection of A and B

Complement Principle

#A = #total - #opposite of A

when things happen at the same time,

multiply

Permutation Equation

n! / (n-r)!

Combination Equation

n! / (n-r)!r!

Number of Circular Permutations Equation

n! / n

Number of Permutations when things are Repeated Equation:

n! / n1!n2!n3!n4!......

What does n and r stand for in nCr?

n=total number, r=number you're picking

Empty Set

set that contains no elements

Fewer permutations result when:

some of the objects being arranged are the same

Intersection

upside down U

when to use complement principle

when you see at least in the question

Multiplication Principle

you can simply multiply two things if they can happen at the same time

Distribution of factorial sign

cant do it

how many cards per suit in a deck?

13

how many letters in alphabet

26

How many cards in a deck?

52

When order isnt important, its called a

Combination

When order is important, its called a

Permutation

Union

U

Complement

a line over anything. The opposite

when things cant happen at the same time,

add the options