9.7 Probability of Compound Events Objective: Find probabilities of unions and intersections of two events, use complementary probabilities

Warm up The school council comprises 3 male students, 5 female students, and 2 teachers. 1. What is the probability that a person chosen at random from the school council is a female student?   2. What is the probability that both members of a committee chosen at random from the school council are male students?

Compound Events A or B A and B Mutually Exclusive

Probability of Compound Events If A and B are two events with an overlap, then: If A and B are mutually exclusive events, then:

Ex. 1: If you draw one card from a deck, find the probability of: Drawing a 4 or a face card Drawing a heart or a face card.

Ex. 1: If you draw one card from a deck, find the probability of: Drawing a 9 or a 10 Drawing an 8 or a spade Drawing an 8 of spades (8 and a spade) Drawing an 8 and a 9

Ex. 2: Two dice are rolled simultaneously. Find: P(5 or 6) P(6 or 12) P(doubles or 10)

Ex. 3: If you draw 2 cards from a deck (without replacement): P(2 hearts or 2 clubs) P(2 clubs or 2 blacks)

Ex. 5: Complementary Events P(not rolling a 2) P(not drawing a ace)