AMDM
Probability Review
Name:___ANSWER KEY_________
1.) There are 97 students enrolled in AMDM at Belton High School. 36 of them currently hold a part time
job and 42 are involved in at least one extra-curricular activity. There are 17 students that work and are
also involved in extra-curriculars. Draw a Venn Diagram of the situation and answer the following
questions:
Has Job
19
Extra-curriculars
25
17
19
19
36
a. How many people are not involved in extra curriculars or have a job?
61
b. What is the probability that a person selected at random from an
AMDM class has a job? (36/97) = .371
c. What is the probability that a person selected at random from an
AMDM class has a job given that they are involved in extra
curriculars? (17/36) = .472
2.) A group of students registered for classes. Information about the classes that they registered for are
displayed in the Venn Diagram below. Use this information to the determine each of the associated
probabilities.
Physics
4
Chemistry
15
2
9
a.
b.
c.
d.
e.
f.
What is the probability that a student studies both subjects? ___(15/30) = .5_________________
What is the probability that a student studies Physics or Chemistry? _____(21/30) = .7_________
What is the probability that a student studies only Physics?_____(4/30)=.133____________
What is the probability that a student studies exactly one subject?__(6/30) = .2_____________
What is the probability that a student studies neither subject?____(9/30) = .3______________
What is the probability that a student studies Chemistry given that they are studying Physics?
________(15/19) = .789_________________________________________________________
AMDM
Probability Review
Name:___ANSWER KEY_________
3.) A box of chocolates contains an equal number of dark and milk chocolates. It has 15 hard centered milk
chocolates, 5 soft centered milk chocolates, 10 hard centered dark chocolates, and 10 soft centered dark
chocolates.
Complete the diagram for randomly selecting a chocolate from a full box.
0.75
0.5
. 50
Milk
Dark
.25
.50
. 50
Hard
Soft
Hard
Soft
a. What is the probability of getting a soft centered dark chocolate? ___(.5*.5) = .25_______
b. What is the probability of getting a hard centered chocolate? _(.5*.75) + (.5 *.5) = .625___
4.) Carl is not having much luck lately. His car will only
start 80% of the time and his motorcycle will only start
60% of the time.
. 80
Car works
. 20
Car
doesn't
start
Complete the tree diagram to model this situation.
a. What is the probability that both the car and
the motorcycle will start? ___(.8*.6) = .48_
b. What is the probability that Carl will have
no choice but use the car? __(.8*.4) = .32
. 60
Motorcycle
Works
. 40
Motorcycle
doesn’t start
. 60
. 40
Motorcycle
Works
Motorcycle
doesn’t start