Tree
diagrams are used to display
all possible outcomes of
experiments involving more than one event.
Tree
diagram: possible outcomes
You
need to decide on your snack. You can have white or chocolate milk
to drink. To eat you can have chocolate chip or oatmeal cookies.
How many different choices do you have?
Combinations 
Drinks 

Cookies 
Possible Outcomes 

2 
x 
2 
4 

Example:
In an
experiment, Philip flips two counters. One side of each counter is
blue and the other is
red. Find all possible outcomes. What is the
probability of both counters landing blue side up? 

You can use a
tree diagram to show all possible outcomes. 
Event 1 
Event 2 
Outcomes 
Write 
First Counter 
Second Counter 






Blue (B) 
Blue
(B) 
Blue,
Blue 
(B, B) 

Red
(R) 
Blue,
Red 
(B,
R) 
Red (R) 
Blue
(B) 
Red,
Blue 
(R,
B) 

Red
(R) 
Red,
Red 
(R,
R) 




Probability of both
blue 
P (B, B)
= 1/4 
1favorable
outcomes 
4
possible
outcomes 
There are
4 possible outcomes.
The probability of both counters landing blue
side up is 1/4. 

Let's
Practice!
click
here
Remember:

A
tree diagram
looks like branches of a tree. 
The order
does not
change the number of outcomes in a tree diagram. 
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