Probability Addition Rule Warm Up

Solving probability problems using addition rule: What is the probability of rolling a 3 or a 5 on a fair six-sided die?

• 1/2

• 1/3

• 1/4

• 1/6

Solving probability problems using addition rule: A bag contains 4 red and 5 blue marbles. What is the probability of drawing a red or a blue marble?

• The probability of drawing a red or a blue marble is 4/9 - 5/9 = -1

• The probability of drawing a red or a blue marble is 4/9 + 5/9 - 0 = 1

• The probability of drawing a red or a blue marble is 4/9 * 5/9 = 20/81

• The probability of drawing a red or a blue marble is 4/9 / 5/9 = 0.8

Events A and B are mutually exclusive. If the probability of event A is 0.4 and the probability of event B is 0.3, what is the probability of A or B occurring?

• 1.0

• 0.5

• 0.7

• 0.2

Solving probability problems using addition rule: In a group of students, 60% like pizza and 40% like burgers. 30% like both pizza and burgers. What is the probability that a student chosen at random likes either pizza or burgers?

• 0.60 - 0.40 = 0.20

• 0.60 x 0.40 = 0.24

• 0.60 / 0.40 = 1.50

• 0.60 + 0.40 - 0.30 = 0.70

Understanding mutually exclusive events: Are rolling a 3 and rolling an even number on a six-sided die mutually exclusive events?

• Only on odd days

• Yes

• Sometimes

• No

If drawing a heart and drawing a spade from a deck of cards are mutually exclusive events, what is the probability of drawing either a heart or a spade?

• 1/3

• 1/2

• 1/4

• 3/4

Are getting a head and getting a tail when flipping a coin mutually exclusive events?

• No

• Yes

In a group of students, 30% play basketball, 40% play soccer, and 10% play both basketball and soccer. What is the probability that a student chosen at random plays either basketball or soccer?

• 0.60

• 0.20

• 0.50

• 0.10

A bag of 12 marbles contains 3 red and 4 blue marbles. What is the probability of drawing a red or a blue marble?

• 5/9

• 2/5

• 7/12

• 3/7

In a standard deck of 52 cards there are 13 diamonds and 13 hearts (red) and 13 spades and 13 clubs (black).  Find the probability of choosing a card at random that is a spade OR a 7

• 1/52
• 1/13
• 4/13
• 17/52