1. 12-7 Probability of Compound Events (Or problems)
Goal:
Find the probability of a compound event.
Eligible Content: A

2. Vocabulary
Prime Numbers – numbers that are only divisible by 1 and the number.
2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41…
The number 1 is NOT prime
The number 2 is the ONLY even prime number

3. Vocabulary
Compound Event – probability of two or more things happening at the same time.
Examples:
Probability of picking red or green marble.
Probability of rolling a 4 on a die and flipping a heads on a coin.

4. Two Types Exclusive – two events cannot happen at the same time.
Probability of rolling a 1 or a 2 on a 6 sided die.
P(1 or 2)
Inclusive – two events can happen at the same time.
Probability of rolling a 2 or an even number.
P(2 or even)

5. Exclusive examples You roll a 10 sided die.
Find the probability of rolling a 4 or an 8.
P(4 or 8) = 0.2
Find the probability of rolling a 9 or less than 3.
P(9 or less than 3) = 0.3

6. Inclusive examples You roll a 10 sided die.
Find the probability of rolling a 5 or an odd number.
P(5 or odd) = 0.5
Find the probability of rolling an odd number or a prime number.
P(odd or prime) = 0.6

7. Mixed Examples
Using a standard deck of cards, find the probability of:
P(jack or king)
Exclusive – 0.15
P(jack or spade)
Inclusive – 0.31
P(4 or red card)
Inclusive – 0.54
P(face card or Ace)
Exclusive – 0.31

8. Mixed Problems
A bag contains cards with the numbers Find the probability of each event.
3 or even number
Multiple of 3 or multiple of 7
Prime number or odd number
6 or factor of 24
5 or 15

9. The French Club has 16 seniors, 12 juniors, 15 sophomores, and 21 freshmen as members. What is the probability that a member chosen at random is a junior or a senior?
A. 0.44
B. 1
C. 0.56
D. 0

10. In Mrs. Kline’s class, 7 boys have brown eyes and 5 boys have blue eyes. Out of the girls, 6 have brown eyes and 8 have blue eyes. If a student is chosen at random from the class, what is the probability that the student will be a boy or have brown eyes?
A. 0.38
B. 0.69
C. 0.54
D. 0.46

11. Practice
Worksheet – “Probabilities of Compound Events”

12. Homework
Worksheet – “Probability of Compound Events Homework”