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