Addition rule for "OR"  Probability
Addition rule for "OR"
Lessons
Notes:
$\cdot$ P(A or B): probability of event A occurring or event B occurring during a single trial.
$\cdot$ If events A, B are mutually exclusive:
 events A, B have no common outcomes.
 in the Venn Diagram, the circle for A and the circle for B have no area of overlap.
 P(A or B) = P(A) + P(B)
$\cdot$ If events A, B are not mutually exclusive:
 events A, B have common outcomes.
 in the Venn Diagram, the circle for A and the circle for B have an area of overlap representing the event "A and B".
 P(A or B) = P(A) + P(B) – P(A and B)

1.
Mutually Exclusive VS. Not Mutually Exclusive
Consider the experiment of rolling a die. 
2.
There are 20 students in a class. 9 students like pizza and 7 students like pasta. Of these students, 3 students like both. Determine the probability that a randomly selected student in the class like pizza or pasta

3.
A card is drawn from a standard deck of 52 cards. Determine the probability that:

4.
Use the following information to determine whether the events A, B are mutually exclusive.