NAME
12-7
DATE
PERIOD
Word Problem Practice
Probability of Compound Events
1. BIRTHDAYS On Juanita’s birthday, her
grandmother sends her a card. What is
the probability that the man who
delivered the mail has a birthday either
the same day or one day before or after?
Disregard February 29 as a possible
birthday, and assume that all days are
equally likely. ≈0.82%
4. MAGIC Iris performs a magic trick in
which she holds a standard deck of cards
and has each of three people randomly
choose a card from the deck. Each person
keeps his or her card as the next person
draws. What is the probability that all
three people will draw a heart?
4
7
J
K
Q
A
6
10
J
9
2
K
6
Q
5
10
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
A
7
4
3
2. SPORTS The World Series is a “best of
seven” game championship in which up
to seven games are played, and one team
has to win four games to win the Series.
In the 2007 World Series, the Boston Red
Sox swept the Colorado Rockies, meaning
that they won the series by winning the
first four games. If you assume that each
team has an equal chance of winning
each game, what is the probability of a
World Series sweep?
8
3
9
2
8
5
5. STOCKS Bruce has just purchased
100 shares of Out Clone, Inc. stock. The
company is seeking FDA approval for a
treatment that relieves the common cold.
According to pharmaceutical experts,
there is a 50% chance that FDA approval
will be granted, and according to market
insiders there is an 85% chance the value
of the stock will double if FDA approval
is granted.
0.0625 or 6.25%
3. BUSINESS At Corrugated Packaging,
Inc., a team of six employees is in charge
of marketing and selling the company’s
products; three are women and three are
men. The president of the company
decides to send four team members to a
national cardboard box conference. He
wants to make sure he chooses names
fairly, so he decides to put the names of
his six sales employees in a hat and draw
four names to see who will go to the
conference. What is the probability that
the team will consist of three women and
one man? 0.2 or 20%
a. What is the probability that the FDA
will approve the treatment and the
value of Bruce’s investment will
double? 0.425 or 42.5%
b. What is the probability that the FDA
will approve the treatment and the
value of your stock will not double?
0.075 or 7.5%
c. Are these events dependent or
independent? Dependent; the
probability that the stock price
will double depends on the
probability that the treatment
will be approved.
Chapter 12
45
Glencoe Algebra 1
Lesson 12-7
0.0129 or 1.29%