7th Grade - Mutually Exclusive Events

In some applications of probability, we may need to calculate the probability of a combination of two or more events. It is therefore necessary to know the relationship between those events and devise some rules to calculate the corresponding probabilities.

For any two events, A and B, we denote
probability that both A and B will occur as P(A and B)
probability that either A or B will occur as P (A or B)

In a sample space, two events are mutually exclusive if they cannot occur at the same time – if a die is rolled:
event A = {odd number}
event B = {even number}

If A and B are two mutually exclusive events, then the probability of A or B occurring is

P(A or B) = P(A) + P(B)

Homework: Exercise 17.2 (page 219) # 1 – 9 
20 minutes - Khan Academy 7th Grade Mission