image PNG : /home/_math/_exercice/d7/7168/metapost/casio.png
SESESESESESESE
SESESESESESESESESESESESESESESE
V3F3V2V3F3F2V1V3F3V2V3F3F2F1
3.
Reminders:
binomial
distribution
E.7155
Here
are
the
choice
trees
associated
with
repeating
a
Bernoulli
test
3
and
4
times
respectively:
1
For
the
threefold
repetition
of
Bernoulli’s
test,
complete
the
table
below
:
Number
of
succès
0
1
2
3
Number
of
issues
2
For
the
four-fold
repetition
of
Bernoulli’s
test,
complete
the
table
below
:
Number
of
succès
0
1
2
3
4
Number
of
issues
E.7121
A
MCQ
(multiple-choice
questionnaire)
is
given
to
students
:
it
contains
three
questions,
and
for
each
question,
four
answers
are
provided,
only
one
of
which
is
cor-rect.
We
want
to
study
the
success
rate
for
this
multiple-choice
questionnaire
if
students
answer
completely
at
random
;
we
therefore
assume
that
the
answers
given
to
each
question
are
independent
of
each
other.
We
note
:
F
i
:
ˇ
The
answer
given
to
question
i
is
false
ı
;
V
i
:
ˇ
The
answer
given
to
question
i
is
true
ı
;
1
Complete
the
weighted
tree
below
:
2
Let
X
be
the
random
variable
that
associates
each
ele-mentary
event
with
the
number
of
correct
answers
ob-tained
in
the
multiple-choice
test.
a
Justify
that
the
random
variable
X
follows
a
binomial
distribution
with
parameters
3
and
0.25
.
b
In
order
to
obtain
the
probability
distribution
of
the
random
variable
X
,
complete
the
table
below
:
k
0
1
2
3
P
X
=
k
c
Calculate
the
expected
value
of
the
random
variable
X
.
E.7168
Reminder
:
for
a
random
variable
X
following
a
binomial
distribution
with
parameters
n
and
p
,
the
probability
that
the
random
variable
takes
the
value
k
is
:
P
X
=
k
=
n
k
·
p
k
·
1
−
p
n
−
k
Note:
the
binomial
coefficient
n
k
allows
us
to
know
the
number
of
paths
in
the
decision
tree
result-ing
in
k
successes
for
n
repetitions.
Above
is
a
screenshot
of
a
calculator
for
calculating
the
bi-nomial
coefficient
5
3
.
1
Using
the
calculator,
determine
the
binomial
coefficients
below
:
a
5
3
b
4
0
c
4
2
d
7
5
2
Consider
the
random
variable
X
following
the
binomial
distribution
with
parameter
B
12
;
0
;
3
.
Determine
the
following
probabilities
rounded
to
10
−
4
:
a
P
X
=3
a
P
X
=7
3
Consider
the
random
variable
X
following
the
binomial
distribution
with
parameter
B
8
;
0
;
4
.
Determine
the
following
probabilities
using
the
complementary
distri-bution,
rounded
to
10
−
4
:
a
P
X
1
a
P
X
7
E.7169
Results
are
rounded
to
the
nearest
10
−
3
.
In
a
watch
factory,
when
the
production
machines
are
prop-erly
adjusted,
4
%
of
the
watches
produced
are
defective.
To
check
the
state
of
production,
10
watches
are
drawn
suc-cessively,
at
random
and
independently
of
each
other.
The
random
variable
associates
the
number
of
defective
watches
with
this
draw.
1
Justify
that
the
random
variable
X
follows
a
binomial
distribution.
Specify
its
parameters.
2
What
is
the
probability
that
at
least
1
watch
is
defective?
We’ll
round
the
value
to
the
nearest
10
−
4
.
4.
Non-symmetrical
tree
https://chingmath.fr
chapExoCorrec/7155
sacados/7155
SESESESESESESE
SESESESESESESESESESESESESESESE
chapExoCorrec/7121
sacados/7121
V3F3V2V3F3F2V1V3F3V2V3F3F2F1
chapExoCorrec/7168
sacados/7168
chapExoCorrec/7169
sacados/7169
::::::AG::::::A:::AG
ALE0;550;37ALGE
E.7133
A
company
was
interested
in
the
probability
of
one
of
its
employees,
chosen
at
random,
being
absent
during
a
given
week
of
winter
2014
.
The
probability
of
an
employee
having
the
flu
in
a
given
week
was
estimated
to
be
0.07
.
If
the
employee
has
the
flu,
then
he
or
she
is
absent.
If
the
employee
does
not
have
the
flu
that
week,
the
probabil-ity
that
he
or
she
will
be
absent
is
estimated
at
0.04
.
An
employee
of
the
company
is
chosen
at
random
and
the
following
events
are
considered
:
G
:
the
employee
has
the
flu
in
a
given
week;
A
:
the
employee
is
absent
in
a
given
week.
1
Reproduce
and
complete
the
tree,
indicating
the
proba-bilities
of
each
branch.
2
Show
that
the
probability
p
(
A
)
of
the
event
A
is
equal
to
0.1072
.
E.7216
In
January
2015
,
the
director
of
a
contemporary
art
museum
commissions
a
survey
on
visitor
habits.
The
museum
has
a
website.
To
purchase
a
ticket,
interested
individuals
can
go
to
the
museum
ticket
office
or
order
a
ticket
online.
Three
types
of
visits
are
available:
Individual
visits
without
an
audio
guide.
Individual
visits
with
an
audio
guide.
Group
visits
for
at
least
10
people.
In
this
case,
a
single
ticket
is
issued
for
the
group.
The
website
only
allows
you
to
purchase
individual
tickets
with
or
without
an
audio
guide.
For
group
visits,
you
must
go
to
the
museum
ticket
office.
Over
the
course
of
the
year
2015
,
the
survey
revealed
that
:
55
%
of
admission
tickets
were
purchased
at
the
museum
ticket
office
;
of
the
tickets
purchased
at
the
museum
ticket
office,
51
%
were
for
individual
visits
without
audio
guide
rental,
and
37
%
were
for
visits
with
audio
guide
rental;
70
%
of
the
tickets
purchased
online
correspond
to
indi-vidual
visits
without
audio
guide
rental.
We
randomly
select
a
museum
ticket
purchased
on
2015
We
consider
the
following
events
:
E
:
ˇ
the
ticket
was
purchased
online
ı
;
A
:
ˇ
the
ticket
is
for
an
individual
visit
with
audio
guide
rental
ı
;
L
:
ˇ
the
ticket
corresponds
to
an
individual
visit
without
audio
guide
rental
ı
;
G
:
ˇ
the
ticket
corresponds
to
a
group
visit
ı
Remember
that
if
E
and
F
are
two
events,
p
(
E
)
denotes
the
probability
of
event
E
and
p
F
(
E
)
denotes
the
probability
of
event
E
given
that
event
F
has
occurred.
We
denote
E
as
the
opposite
event
of
E
.
1
Copy
and
complete
the
following
weighted
tree
represent-ing
the
situation
described
in
the
statement
:
2
Show
that
the
probability
that
the
ticket
was
purchased
online
and
corresponds
to
an
individual
visit
with
audio
guide
rental
is
equal
to
0.135
.
3
Show
that
:
p
(
A
)
=
0.3385
4
The
ticket
chosen
corresponds
to
an
individual
visit
with
audio
guide
rental.
What
is
the
probability
that
this
ticket
was
purchased
at
the
museum
ticket
office?
The
result
will
be
rounded
to
the
nearest
thousandth
5.
Conditional
probability
and
binomial
distribution
E.7136
A
large
company
has
just
com-pleted
its
recruitment
campaign,
which
took
place
in
two
stages
:
first
stage
:
review
of
the
candidate’s
application
;
second
stage
:
interview
for
recruitment
purposes.
The
recruitment
process
implemented
by
the
company
is
as
follows
:
if
the
application
is
deemed
to
be
of
good
quality,
the
candidate
is
invited
to
an
interview
with
the
human
re-sources
director
;
if
the
application
is
not
deemed
to
be
of
good
quality,
the
candidate
undergoes
tests
and
is
then
invited
to
an
interview
with
the
company
director.
In
both
cases,
at
the
end
of
the
interview,
the
candidate
is
either
hired
or
not.
By
choosing
a
candidate
at
random,
we
construct
a
random
experiment
whose
probability
tree
is
represented
below
with
some
of
the
data
retrieved
from
the
publication
:
https://chingmath.fr
chapExoCorrec/7133
sacados/7133
::::::AG::::::A:::AG
chapExoCorrec/7216
sacados/7216
ALE0;550;37ALGE
chapExoCorrec/7136
sacados/7136
0;3:::RPDR0;24:::RD0;7:::RPDR::::::RD
0;950;7S0;3SR0;050;2S0;8SR
where
D
is
the
event
ˇ
the
candidate
has
a
file
that
is
consid-ered
to
be
of
good
quality
ı
ı
and
R
is
the
event
"
the
candidate
is
hired
by
the
company
ı.
1
a
Determine
the
probability
P
D
R
.
b
Furthermore,
we
know
that
38
%
candidates
were
hired.
Deduce
the
probability
P
D
R
.
c
Complete
the
probability
tree
2
Ten
people
apply
for
a
job
at
the
company.
Their
ap-plications
are
reviewed
independently
of
each
other.
Let
X
be
the
random
variable
giving
the
number
of
people
recruited
from
among
the
10
applicants.
a
Justify
that
X
follows
a
binomial
distribution
with
pa-rameters
n
=10
and
p
=0.38
.
b
Calculate
the
probability
that
at
least
one
of
the
ten
people
will
be
hired.
Give
the
exact
value,
then
a
value
rounded
to
10
−
3
.
E.7139
A
survey
was
conducted
among
students
enrolled
in
a
high
school
lunch
program.
The
results
were
used
to
construct
the
probability
tree
below
:
A
student
is
chosen
at
random
from
among
those
enrolled
in
the
lunch
program.
We
note
the
following
events
:
R
the
event
:
ˇ
the
student
regularly
eats
in
the
cafete-ria
ı
;
S
the
event
:
ˇ
the
student
is
satisfied
ı.
We
note
R
and
S
as
the
opposite
events
of
R
and
S
.
1
a
Show
that
the
probability
of
event
S
is
equal
to
0.675
.
b
Knowing
that
the
student
is
not
satisfied
with
the
qual-ity
of
the
meals,
calculate
the
probability
that
he
eats
regularly
in
the
cafeteria.
Give
the
result
rounded
to
10
−
3
.
2
Four
students
are
randomly
selected
from
among
those
enrolled
in
the
half-board
program
and
questioned
suc-cessively
and
independently.
Let
X
be
the
random
variable
equal
to
the
number
of
students
who
say
they
are
satisfied
with
the
quality
of
the
meals.
Since
the
number
of
students
is
large
enough,
we
consider
that
X
follows
a
binomial
distribution.
The
results
will
be
rounded
to
three
decimal
places.
a
Specify
the
parameters
of
this
binomial
distribution
b
Calculate
the
probability
of
event
A
:
ˇ
all
four
students
are
satisfied
with
the
quality
of
the
meals
ı.
c
Describe
event
A
in
one
sentence
and
calculate
its
prob-ability.
https://chingmath.fr
0;3:::RPDR0;24:::RD0;7:::RPDR::::::RD
chapExoCorrec/7139
sacados/7139
0;950;7S0;3SR0;050;2S0;8SR
0;650;3E0;7EH0;350;6E0;4EF
E.7217
A
mobile
phone
operator
is
orga-nizing
a
telephone
marketing
campaign
to
offer
its
customers
a
new
subscription
plan.
Some
of
the
people
contacted
listen
to
the
explanation,
while
others
hang
up
immediately
(or
say
they
are
not
interested)
.
A
person
is
chosen
at
random
from
the
customer
database.
Each
person
has
the
same
probability
of
being
chosen.
We
denote
H
the
event
ˇ
the
person
chosen
is
a
man
ı,
F
the
event
ˇ
the
person
chosen
is
a
woman
ı,
E
the
event
"
the
person
chosen
listens
to
the
salesperson’s
explanations
ı
and
E
the
opposite
event
of
E
.
Reminder
of
notation:
If
A
and
B
are
two
given
events,
P
(
A
)
denotes
the
probabil-ity
that
event
A
will
occur
and
P
B
A
denotes
the
probabil-ity
of
event
A
occurring,
given
that
event
B
has
occurred.
Part
A
The
study
has
established
the
following
probability
tree
:
For
each
statement,
only
one
of
the
answers
is
correct.
Copy
the
number
of
the
answer
and
the
value
chosen
onto
your
answer
sheet.
No
justification
is
required
1
The
probability
that
the
person
chosen
will
listen
to
the
salesperson’s
explanations
is
equal
to
:
a
0
;
195
b
0
;
21
c
0
;
405
d
0
;
595
2
The
salesperson
addresses
a
person
who
listens
to
them.
The
probability,
rounded
to
two
decimal
places,
that
this
person
is
a
man
is
equal
to
:
a
0
;
48
b
0
;
52
c
0
;
76
d
0
;
24
Part
B
The
surveys
conducted
during
these
first
few
days
also
show
that
12
%
of
those
interviewed
subscribe
to
this
new
package.
Each
employee
of
the
operator
makes
60
calls
per
day.
We
assume
that
the
file
is
large
enough
for
the
choices
to
be
considered
independent
and
made
under
identical
conditions.
Let
X
be
the
random
variable
that
counts
the
number
of
sub-scriptions
made
by
a
given
employee
on
a
given
day.
1
Justify
that
the
random
variable
X
follows
a
binomial
distribution,
the
parameters
of
which
will
be
given.
2
Determine
the
probability
that
the
employee
will
obtain
5
subscriptions
on
a
given
day.
(The
result
will
be
rounded
to
two
decimal
places.)
3
Determine
the
probability
that
the
employee
will
obtain
at
least
one
subscription
on
a
given
day.
(The
value
will
be
rounded
to
the
nearest
ten-thousandth)
.
E.7312
A
survey
was
carried
out
among
students
at
a
high
school
to
find
out
their
views
on
the
length
of
the
lunch
break
and
school
rhythms.
The
survey
revealed
that
56.75
%
of
the
school’s
students
were
in
favor
of
spread-ing
classes
out
over
the
school
year.
Four
students
taken
at
random
from
among
the
school’s
pupils
are
interviewed
successively
and
independently.
Let
X
be
the
random
variable
that
gives
the
number
of
students
in
favor
of
a
more
staggered
distribution
of
classes
over
the
school
year.
As
the
number
of
students
is
sufficiently
large,
X
is
considered
to
follow
a
binomial
distribution.
1
Specify
the
parameters
of
this
binomial
distribution.
Results
will
be
rounded
to
the
nearest
10
−
4
.
2
Calculate
the
probability
that
none
of
the
four
students
surveyed
is
in
favor
of
spreading
classes
out
more
over
the
school
year.
3
Calculate
the
probability
that
exactly
two
students
are
in
favor
of
a
more
spread-out
course
distribution
over
the
school
year.
E.7137
A
large
company
has
just
com-pleted
its
recruitment
campaign,
which
took
place
in
two
stages
:
first
stage
:
review
of
the
candidate’s
application
;
second
stage
:
interview
for
recruitment
purposes.
The
recruitment
process
implemented
by
the
company
is
as
follows
:
if
the
application
is
deemed
to
be
of
good
quality,
the
candidate
is
invited
to
an
interview
with
the
human
re-sources
director
;
if
the
application
is
not
deemed
to
be
of
good
quality,
the
candidate
undergoes
tests
and
is
then
invited
to
an
interview
with
the
company
director.
In
both
cases,
at
the
end
of
the
interview,
the
candidate
is
either
hired
or
not.
At
the
end
of
this
recruitment
campaign,
the
company
pub-lishes
the
following
results
:
30
%
of
the
candidates
had
applications
that
were
deemed
to
be
of
good
quality;
20
%
candidates
whose
applications
were
not
considered
to
be
of
good
quality
were
recruited
;
38
%
candidates
were
recruited.
1
We
take
a
random
candidate
and
note
:
D
the
event
ˇ
the
candidate
has
a
file
that
is
considered
to
be
of
good
quality
ı
;
R
the
event
ˇ
the
candidate
is
hired
by
the
company
ı.
a
Represent
this
situation
using
a
weighted
tree
b
Calculate
the
probability
that
the
candidate
does
not
have
a
good
application
and
is
not
hired
by
the
com-pany.
c
Show
that
the
probability
of
event
D
∩
R
is
equal
to
0.24
.
d
Deduce
the
probability
that
a
candidate
will
be
hired
given
that
their
application
is
considered
to
be
of
good
quality.
Complete
the
weighted
tree
created
in
ques-
https://chingmath.fr
chapExoCorrec/7217
sacados/7217
0;650;3E0;7EH0;350;6E0;4EF
chapExoCorrec/7312
sacados/7312
chapExoCorrec/7137
sacados/7137
Extrait de Centres Etrangers
Juin 2014
EvènementsélémentairesNNNNNNNBBNNNNNNNNBBNBNNBNNBBBB1ertirage2etirage
3XV2F2F2FV2V1F1F1FF2V1F1F1FF2V1F1F1FFV2V1F1F1FV1V0F0F0FF1V0F0F0FF1V0F0F0FFF2V1F1F1FV1V0F0F0FF1V0F0F0FF1V0F0F0FFF2V1F1F1FV1V0F0F0FF1V0F0F0FF1V0F0F0FFF
tion
a
.
2
Ten
people
apply
for
a
job
at
the
company.
Their
ap-plications
are
reviewed
independently
of
each
other.
Let
X
be
the
random
variable
giving
the
number
of
people
hired
among
the
10
applicants.
a
Justify
that
X
follows
a
binomial
distribution
with
pa-rameters
n
=10
and
p
=0.38
.
b
Calculate
the
probability
that
at
least
one
of
the
ten
people
will
be
hired.
Give
the
exact
value,
then
a
value
rounded
to
10
−
3
.
6.
Independent
repetition
of
identical
experiments
E.7683
Consider
a
random
experiment
with
two
outcomes
:
S
success
and
E
failure.
These
two
outcomes
are
equiprobable.
We
repeat
this
experiment
4
times
independently.
The
choice
tree
below
is
used
to
describe
this
repetition:
1
How
many
different
outcomes
does
this
random
experi-ment
have?
2
Determine
the
probability
of
obtaining
4
success.
3
a
How
many
outcomes
represent
3
success?
b
Determine
the
probability
of
obtaining
3
success
in
this
random
experiment.
E.7423
An
urn
contains
two
black
balls
and
one
white
ball;
the
game
is
played
with
the
ball
being
re-turned
:
i.e.,
once
the
ball
has
been
drawn,
it
is
returned
to
the
urn
before
the
next
draw.
Here’s
a
decision
tree
based
on
the
drawing
of
two
balls
:
1
Taking
into
account
the
order
in
which
the
balls
are
drawn,
what
is
the
possible
number
of
different
draws?
2
Determine
the
probability
of
the
following
events
:
a
A
:
ˇ
The
first
ball
drawn
is
blanche
ı.
b
B
:
ˇ
The
two
balls
drawn
are
différentes
ı
colors.
c
C
:
ˇ
The
second
ball
is
a
noire
ı
ball.
3
Give
the
probabilities
of
the
following
events
:
a
A
∩
B
b
B
c
C
7.
Independent
repetition
of
identical
experiments
and
random
variables
E.7386
Consider
a
multiple-choice
question-naire
consisting
of
3
questions
each
offering
4
answers,
only
one
of
which
is
correct.
A
random
experiment
is
created
by
asking
participants
to
randomly
answer
the
questions
proposed
in
the
form.
This
situation
is
represented
by
the
choice
tree
below
:
https://chingmath.fr
chapExoCorrec/7683
sacados/7683
chapExoCorrec/7423
sacados/7423
EvènementsélémentairesNNNNNNNBBNNNNNNNNBBNBNNBNNBBBB1ertirage2etirage
chapExoCorrec/7386
sacados/7386
3XV2F2F2FV2V1F1F1FF2V1F1F1FF2V1F1F1FFV2V1F1F1FV1V0F0F0FF1V0F0F0FF1V0F0F0FFF2V1F1F1FV1V0F0F0FF1V0F0F0FF1V0F0F0FFF2V1F1F1FV1V0F0F0FF1V0F0F0FF1V0F0F0FFF
EvènementsélémentairesNNNNNNNNBNNBNNNNNNNNNBNNBNNNBNNNBNBNBBBNNNNNNNNNBNNBNNNNNNNNNBNNBNNNBNNNBNBNBBBNNBNNNBNNBBNBNNBNNNBNNBBNBNNBBNNBBNBBBBBB
V3F3V2V3F3F2V1V3F3V2V3F3F2F1
For
each
elementary
event,
the
random
variable
X
is
associ-ated
with
the
number
of
correct
answers.
Give
the
probability
distribution
of
the
random
variable
X
.
E.5169
There
are
three
balls
in
an
urn
:
two
black
balls
and
one
white
ball.
Three
balls
are
drawn
succes-sively
from
this
urn,
with
replacement.
The
decision
tree
below
illustrates
all
the
elementary
events
of
this
random
experiment
:
Each
draw
is
associated
with
a
payoff
as
follows
:
0
e
if
no
black
balls
are
drawn
;
1
e
if
only
one
black
ball
is
drawn
;
2
e
if
two
black
balls
are
drawn
;
5
e
if
all
three
balls
are
black.
We
consider
the
random
variable
X
which
associates
each
draw
with
the
corresponding
prize.
Complete
the
table
below
giving
the
distribution
of
the
ran-dom
variable
X
:
k
0
1
2
5
P
X
=
k
8.
Expectations,
variances
and
independent
repetition
of
identical
experiments
E.5190
A
QCM
(multiple-choice
question-naire)
is
proposed
to
students
:
it
com-prises
three
questions
and
for
each
of
these
questions,
four
answers
are
pro-posed,
of
which
only
one
is
correct.
We
wish
to
study
the
percentage
of
success
in
this
MCQ
if
the
students
answer
it
completely
at
random
;
we
then
assume
that
the
answers
given
to
each
of
the
questions
are
independent
of
each
other.
We
note
:
F
i
:
ˇ
The
answer
provided
to
question
i
is
fausse
ı
;
V
i
:
ˇ
The
answer
provided
to
the
question
i
is
vraie
ı
;
1
Complete
the
weighted
tree
shown
above.
2
We
note
X
the
random
variable
counting
the
number
of
correct
answers
provided
to
the
MCQ.
a
Determine
the
probability
distribution
of
the
random
variable
X
.
b
Calculate
the
expectation
of
the
random
variable
X
.
E.5913
A
company
produces
electronic
components
before
êbeing
as-signed
to
sales.
Each
component
undergoes
two
independent
quality
tests
:
5
%
of
the
components
fail
the
first
test
;
3
%
of
the
components
fail
the
second
test.
At
the
end
of
the
production
line,
an
electronic
component
is
chosen
at
random.î
1
Determine
the
probability
that
the
electronic
component
failed
both
tests.
0.0012
0.0013
0.0014
0.0015
2
Determine
the
probability
that
the
electronic
component
failed
only
one
of
the
two
tests.
0.0666
0.077
0.0776
0.078
3
The
coût
of
production
is
calculated
as
follows
:
each
component
coûte
100
e
and
for
each
failed
test,
the
re-pair
coûte
10
e
.
Let
X
be
the
random
variable
that
associates
each
ran-domly
selected
component
with
its
production
cost
coût.
What
is
the
expected
value
of
the
random
variable
X
?
100.8
101.8
102.8
103.8
https://chingmath.fr
chapExoCorrec/5169
sacados/5169
EvènementsélémentairesNNNNNNNNBNNBNNNNNNNNNBNNBNNNBNNNBNBNBBBNNNNNNNNNBNNBNNNNNNNNNBNNBNNNBNNNBNBNBBBNNBNNNBNNBBNBNNBNNNBNNBBNBNNBBNNBBNBBBBBB
chapExoCorrec/5190
sacados/5190
V3F3V2V3F3F2V1V3F3V2V3F3F2F1
chapExoCorrec/5913
sacados/5913
Urne AUrne B123
P(CP(PPP(PPCP(CP(PPP(PPC
::::::R:::VB::::::R:::VN
E.5914
A
company
manufactures
electronic
components.
During
pro-duction,
each
component
undergoes
two
quality
tests.
If,
during
one
of
the
tests,ôthe
test
is
negative,
the
component
is
repaired
and
returned
to
the
production
line.
6
%
of
components
fail
the
first
test.
;
2
%
of
components
fail
the
second
test.
At
the
end
of
the
production
line,
an
electronic
component
is
chosen
at
random.î
1
Determine
the
probability
that
the
electronic
component
failed
both
tests.
0.0012
0.0013
0.0014
0.0015
2
Determine
the
probability
that
the
electronic
component
failed
only
one
of
the
two
tests.
0.0666
0.077
0.0776
0.078
3
The
coût
of
production
is
calculated
as
follows
:
each
component
coûte
100
e
and
for
each
failed
test,
the
re-pair
coûte
10
e
.
Let
X
be
the
random
variable
that
associates
each
ran-domly
selected
component
with
its
production
cost
coût.
What
is
the
expected
value
of
the
random
variable
X
?
100.8
101.8
102.8
103.8
9.
Independent
succession
of
random
experiments
E.5915
Consider
two
urns
A
and
B
contain-ing
four
and
three
objects
respectively
as
shown
below
:
The
game
consists
of
drawing
an
object
from
urn
A
then
from
urn
B
:
1
How
many
different
pairs
of
objects
can
be
obtained
from
the
two
draws?
2
Consider
the
following
two
events
:
C
:
ˇ
The
pair
of
objects
includes
a
carré
ı
P
:
ˇ
the
pair
of
objects
includes
a
pentagone
ı
Determine
the
following
probabilities
:
a
P
(
C
∩
P
)
b
P
(
C
∩
P
)
c
P
(
C
∩
P
)
d
P
(
C
∩
P
)
3
a
Determine
the
following
two
probabilities
:
P
(
C
)
;
P
(
P
)
b
Copy
and
complete
the
tree
below
with
the
probabilities
shown
:
c
Can
we
find
the
results
of
ques-tion
2
using
the
probability
tree
from
the
previous
question.
E.5191
Two
urns
A
and
B
are
available,
each
containing
balls
indistinguishable
by
touch.
Here
is
the
composition
of
the
urns
:
Urn
A
:
three
black
balls
and
two
white
balls
;
Urn
B
:
five
red
balls
and
two
green
balls.
One
ball
is
drawn
successively
from
each
of
the
urns.
Consider
the
following
events
:
B
:
ˇ
the
ball
drawn
is
blanche
ı
;
N
:
ˇ
the
ball
drawn
is
noire
ı
;
R
:
ˇ
the
ball
drawn
is
rouge
ı
;
V
:
ˇ
the
ball
drawn
is
verte
ı.
1
Copy
and
complete
the
probability
tree
below
:
2
Determine
the
value
of
the
following
probabilities
:
a
P
(
B
∩
R
)
b
P
(
B
∩
V
)
c
P
(
N
∩
R
)
3
a
Give
the
value
of
:
P
(
B
∩
R
)+
P
(
N
∩
R
)
.
b
What
do
we
notice?
https://chingmath.fr
chapExoCorrec/5914
sacados/5914
chapExoCorrec/5915
sacados/5915
Urne AUrne B123
P(CP(PPP(PPCP(CP(PPP(PPC
chapExoCorrec/5191
sacados/5191
::::::R:::VB::::::R:::VN
CBA
ABACACABA
E.5168
A
small
restaurant
offers
three
main
courses
and
two
desserts
on
its
menu.
Here
is
a
description
of
the
menu
:
Spaghetti
.
.
.
.
.
.
.6
e
Beef
fillet
.
.
.
.
.
.
.7
e
Rib
steak
.
.
.
.
.
.
.8
e
Fruit
salad
.
.
.
.
.
.
.
.2
e
Custard
.
.
.
.
.
.
.
.
.
.
3
e
Each
customer
entering
the
restaurant
orders
exactly
one
main
course
and
one
dessert.
1
Taking
a
random
customer
leaving
the
restaurant,
spec-ify
what
their
bill
might
be.
2
Assuming
that
all
combinations
main
course
=
dessert
have
the
same
probability
of
being
chosen
by
a
customer.
a
How
many
combinations
can
be
created
from
this
menu?
b
What
is
the
probability
that
a
customer
paid
8
e
?
11
e
?
c
Show
that
the
probability
of
having
a
bill
for
10
e
is
1
3
.
d
Complete
the
table
below
:
Invoice
amount
8
9
10
11
Probability
E.5350
A
tourist
travels
for
two
days
to
the
Pacific
coast
of
Mexico
in
the
locality
of
ˇ
Faro
de
Bucerias
ı.
On
the
way
to
the
beach,
two
paths
are
offered
to
the
beaches
of
ˇ
Maruata
ı
and
ˇ
Playa
Ventura
ı.
On
the
first
day,
the
tourist
chooses
one
of
the
two
beaches
at
random.
On
the
second
day,
he
will
change
beaches
with
probability
3
4
.
What
is
the
probability
that
the
tourist
has
been
to
the
beach
ˇ
Playa
Ventura
ı
at
least
once?
E.6633
An
elephant
moves
to
three
points
in
its
territory.
It
starts
at
point
A
and
makes
three
moves
:
Either,
he
turns
clockwise
with
2
chances
out
of
three
other-wise,
he
moves
counterclockwise.
It
is
assumed
that
each
of
his
moves
is
independent
of
the
previous
ones.
What
is
the
probability
that,
at
the
end
of
these
moves,
he
will
arrive
at
the
point
B
?
10.
Random
variables
and
repetitions
of
independent
experiments
E.133
lebanon
-
2004
-
choice
-
7
points
In
an
animal
experiment,
a
rat
is
placed
at
the
start
of
a
run
and
asked
to
choose
one
of
3
exit
doors
:
if
it
borrows
the
door
A
,
it
goes
out
if
he
borrows
one
of
the
doors
B
or
C
,
he
is
brought
back
to
the
start,
and
this
until
he
chooses
the
door
A
.
We’ll
give
the
results
as
irreducible
fractions
Part
A
:
It
is
assumed
that
the
rat
has
no
memory:
it
chooses
a
door
at
random
and
can
borrow
the
same
door
several
times
in
a
row.
Each
door
therefore
has
the
same
probability
of
being
chosen.
1
What
is
the
probability
that
it
will
come
out
on
the
first
try?
2
What
is
the
probability
that
he
only
comes
out
on
the
second
try
(the
first
being
missed
and
the
second
being
successful)
?
3
What
is
the
probability
that
it
only
comes
out
on
the
fourth
try?
Part
B:
It
is
assumed
that
the
rat
has
a
perfect
memory:
at
each
step,
it
randomly
chooses
one
of
the
doors
it
has
never
been
through.
1
On
the
appendix
below
(return
with
copy)
,
complete
the
tree
with
the
weightings.
2
X
denotes
the
number
of
trials
it
takes
to
exit.
What
values
can
the
number
X
take?
3
Complete
the
table
below
:
Value
of
X
1
2
3
Probability
1
3
https://chingmath.fr
chapExoCorrec/5168
sacados/5168
chapExoCorrec/5350
sacados/5350
chapExoCorrec/6633
sacados/6633
CBA
sacados/133
Liban - 2004 - au choix - 7 points
ABACACABA
V3F3V2V3F3F2V1V3F3V2V3F3F2F1
-1-22
112
E.4797
A
balanced
die
has
letters
written
on
its
faces
:
two
A
,
two
B
and
two
C
.
The
random
experiment
consists
of
rolling
the
die
three
times
and
noting,
each
time,
the
letter
of
the
hidden
face.
Thus,
at
each
output
of
the
random
experiment,
a
three-letter
word
is
constructed.
1
Describe
the
27
mots
that
can
be
obtained
in
this
random
experiment.
It
is
assumed
that
each
of
these
words
has
the
same
probabil-ity
of
exit.
2
Give
the
probability
of
the
following
events
:
a
A
:
ˇ
Le
word
obtained
contains
exactly
once
the
letter
B
ı
;
b
B
:
ˇ
The
word
obtained
contains
exactly
twice
the
let-ter
B
ı
;
c
C
:
ˇ
The
word
contains
the
same
letter
in
the
first
and
third
place
ı.
3
Based
on
the
construction
of
these
words,
we
have
cre-ated
a
new
game
with
the
following
rules
:
The
player
wins
2
e
if
the
word
contains
the
letter
only
once
B
;
the
player
wins
5
e
if
the
word
contains
exactly
two
instances
of
the
letter
B
.
The
player
wins
10
e
if
the
word
is
ˇ
BBB
ı.
We
note
ˇ
X
=
k
ı
the
event
ˇ
the
player
wins
k
e
ı.
Com-plete
the
table
below
:
k
0
2
5
10
P
(
X
=
k
)
11.
Random
variables,
expectations,
standard
deviations
and
repetitions
E.4811
A
QCM
(multiple-choice
questionnaire)
is
proposed
to
students
:
it
comprises
three
questions
and
four
answers
are
proposed,
only
one
of
which
is
correct.
We
wish
to
study
the
percentage
of
success
in
this
MCQ
if
the
students
answer
it
completely
at
random
;
we
then
assume
that
the
answers
given
to
each
of
the
questions
are
indepen-dent
of
each
other.
We
note
:
F
i
:
ˇ
The
answer
provided
to
question
i
is
fausse
ı
;
V
i
:
ˇ
The
answer
provided
to
the
question
i
is
vraie
ı
;
1
Complete
the
probability
tree
below
:
2
Note
X
the
random
variable
counting
the
number
of
cor-rect
answers
provided
to
the
MCQ.
a
Determine
the
probability
distribution
of
the
random
variable
X
.
b
Calculate
the
expectation
of
the
random
variable
X
.
E.7501
An
urn
contains
three
balls
indistin-guishable
to
the
touch
bearing
the
num-bers
−
2
,
−
1
and
2
.
Consider
the
random
experiment
of
suc-cessively
drawing
a
ball
from
the
urn
three
times
and
putting
it
back
each
time.
Consider
the
random
variable
X
which
associates
with
each
experiment,
the
sum
of
the
numbers
obtained
on
the
balls
drawn.
Determine
the
expectation
of
the
random
variable
X
Any
trace
of
research
or
initiative,
however
incomplete,
will
be
taken
into
account
in
the
assessment.
E.7562
An
urn
contains
three
balls
indistin-guishable
to
the
touch
bearing
the
num-bers
1
,
1
and
2
.
Consider
the
random
experiment
of
suc-cessively
drawing
a
ball
from
the
urn
three
times
and
putting
it
back
each
time.
Consider
the
random
variable
X
which
associates
with
each
experiment,
the
sum
of
the
numbers
obtained
on
the
balls
drawn.
Determine
the
expectation
of
the
random
variable
X
Any
trace
of
research
or
initiative,
however
incomplete,
will
be
taken
into
account
in
the
assessment.
https://chingmath.fr
chapExoCorrec/4797
sacados/4797
chapExoCorrec/4811
sacados/4811
V3F3V2V3F3F2V1V3F3V2V3F3F2F1
chapExoCorrec/7501
sacados/7501
-1-22
chapExoCorrec/7562
sacados/7562
112
E.5196
A
chocolate
factory
produces
boxes
of
chocolates
each
year,
including
50
%
with
milk
chocolate,
30
%
with
dark
chocolate,
and
20
%
with
white
chocolate.
70
%
of
the
boxes
contain
plain
chocolates,
while
the
others
contain
chocolates
filled
with
caramel.
These
proportions
are
independent
of
the
type
of
chocolate
used
to
make
the
box.
Consider
the
following
events
:
L
:
ˇ
milk
chocolate
is
used
ı
;
N
:
ˇ
dark
chocolate
is
used
ı
;
B
:
ˇ
white
chocolate
is
used
ı
;
Na
:
ˇ
the
chocolates
are
plain
ı
;
C
:
ˇ
the
chocolates
are
filled
with
caramel
ı
;
All
results
will
be
given
in
decimal
form.
1
Draw
the
weighted
tree
associated
with
this
situation.
2
A
box
is
chosen
at
random
from
the
factory
output.
De-termine
the
probabilities
of
the
following
events
:
a
ˇ
the
box
contains
dark
and
natures
ı
chocolates.
b
ˇ
the
box
contains
dark
or
plain
chocolates
ı
3
The
company
sets
box
prices
as
follows
:
le
base
price
for
a
box
of
chocolate
is
9
e
;
if
the
chocolate
used
is
dark
chocolate
then
the
price
is
increased
by
4
e
;
if
the
chocolate
used
is
white
chocolate
then
the
price
is
increased
by
2
e
;
if
the
chocolates
are
caramel-filled,
the
price
per
box
increases
by
2
e
.
The
random
variable
X
associates
a
box
produced
by
the
factory
with
its
belly
price.
a
Draw
the
table
representing
the
probability
distribu-
tion
associated
with
the
random
variable
X
.
b
Determine
the
expectation
of
the
random
variable
X
round
to
the
nearest
tenth.
E.6631
A
nursery
offers
three
types
of
trees
:
acacias,
plane
trees,
and
oaks.
Each
of
these
trees
can
be
pur-chased
in
different
sizes
:
either
as
a
ˇ
young
sapling
ı
(
0.75
meters)
,
or
as
an
ˇ
mature
tree
ı
(
2
meters)
.
At
the
âsapling
stage,
acacias,
plane
trees,
and
oaks
are
worth
50
e
,
65
e
and
80
e
respectively.
If
the
customer
wants
to
buy
the
adult
form,
they
must
add
15
e
.
In
his
end-of-year
review,
he
notes
that
40
%
of
the
trees
sold
are
oaks
and
that
acacias
and
plane
trees
share
the
remaining
sales
equally.
He
also
notices
that,
regardless
of
the
type
of
tree,
a
quarter
of
sales
are
always
made
on
"
adult
ı.
The
random
experiment
considered
consists
of
randomly
drawing
an
invoice
from
the
financial
year
2015
.
The
following
events
are
considered
:
A
:
ˇ
The
tree
purchased
is
a
acacia
ı
P
:
ˇ
The
tree
purchased
is
a
platane
ı
C
:
ˇ
The
tree
purchased
is
a
chêne
ı
J
:
ˇ
The
tree
is
a
sapling
ı
1
Draw
a
weighted
tree
representing
this
situation
2
Consider
the
random
variable
X
associating
the
invoice
drawn
with
its
amount.
a
Draw
the
table
of
the
probability
distribution
of
the
random
variable
X
.
b
Calculer
the
expectation
of
the
random
variable
X
.
c
Donner
the
standard
deviation
of
X
to
the
nearest
tenth.
12.
Random
variables,
expectations,
standard
deviations
and
conditional
proba-bilities
E.4890
A
chocolate
factory
produces
boxes
of
chocolate
throughout
the
year,
of
which
50
%
are
made
with
milk
chocolate,
30
%
with
dark
chocolate,
and
20
%
with
white
chocolate.
70
%
of
the
boxes
contain
plain
chocolates,
while
the
others
contain
caramel-filled
chocolates.
These
proportions
are
inde-pendent
of
the
type
of
chocolate
used
to
make
the
box.
Consider
the
following
events
:
L
:
ˇ
milk
chocolate
is
used
ı
;
N
:
ˇ
dark
chocolate
is
used
ı
;
B
:
ˇ
white
chocolate
is
used
ı
;
Na
:
ˇ
the
chocolates
are
plain
ı
;
C
:
ˇ
the
chocolates
are
filled
with
caramel
ı
;
All
results
will
be
given
in
decimal
form.
1
Draw
the
probability
tree
associated
with
this
situation.
2
A
box
is
chosen
at
random
from
the
factory
output.
De-termine
the
probabilities
of
the
following
events
:
a
ˇ
The
box
contains
dark
and
plain
chocolates
ı
b
ˇ
The
box
contains
dark
or
plain
chocolates
ı
3
The
company
sets
the
prices
of
the
boxes
as
follows
:
the
base
price
of
a
box
of
chocolates
is
9
e
;
if
dark
chocolate
is
used,
the
price
is
increased
by
4
e
;
if
white
chocolate
is
used,
the
price
is
increased
by
2
e
;
if
the
chocolates
are
filled
with
caramel,
the
price
of
the
box
increases
by
2
e
.
The
random
variable
X
associates
each
box
produced
by
the
factory
with
its
selling
price.
a
Draw
a
table
representing
the
probability
distribution
associated
with
the
random
variable
X
.
b
Determine
the
expected
value
of
the
random
variable
X
.
https://chingmath.fr
chapExoCorrec/5196
sacados/5196
chapExoCorrec/6631
sacados/6631
chapExoCorrec/4890
sacados/4890
CCMCCTCCP
E.7561
A
nursery
offers
three
types
of
trees
:
acacias,
plane
trees,
and
oaks.
Each
of
these
trees
can
be
purchased
in
different
sizes
:
either
as
a
ˇ
young
sapling
ı
(
0.75
meters)
,
or
as
an
ˇ
mature
tree
ı
(
2
meters)
.
At
the
âsapling
stage,
acacias,
plane
trees,
and
oaks
are
worth
50
e
,
65
e
and
80
e
respectively.
If
the
customer
wants
to
buy
the
adult
form,
they
must
add
15
e
.
During
his
end-of-year
review,
he
notes
that
40
%
of
the
trees
sold
are
oaks
and
that
acacias
and
plane
trees
share
the
re-maining
sales
equally.
He
also
notices
that
regardless
of
the
type
of
tree,
a
quarter
of
sales
are
always
for
"
adult
ı.
The
random
experiment
considered
consists
of
randomly
drawing
an
invoice
from
the
fiscal
year
2015
.
Consider
the
following
events
:
A
:
ˇ
The
tree
purchased
is
an
acacia
ı
P
:
ˇ
The
tree
purchased
is
a
plane
tree
ı
C
:
ˇ
The
tree
purchased
is
an
oak
tree
ı
J
:
ˇ
The
tree
is
a
young
sapling
ı
1
a
Draw
a
weighted
tree
representing
this
situation
b
Give
the
probability
of
the
event
C
∩
J
2
We
consider
the
random
variable
X
associating
the
in-voice
drawn
with
its
amount.
a
Draw
up
the
probability
distribution
table
for
the
ran-dom
variable
X
.
b
Calculate
the
expected
value
of
the
random
variable
X
.
E.4822
A
restaurant
offers
two
types
of
dessert
on
its
menu
:
an
assortment
of
macarons,
chosen
by
50
%
customers
;
a
slice
of
tarte
tatin,
chosen
by
30
%
customers.
the
rest
of
the
customers
do
not
order
any
dessert.
No
customer
orders
more
than
one
dessert.
In
addition,
80
%
customers
have
coffee,
regardless
of
whether
or
not
they
have
dessert.
A
customer
at
this
restaurant
is
randomly
surveyed.
We
note
p
the
probability
associated
with
this
random
experiment.
We
note
:
M
the
event
:
ˇ
The
customer
orders
an
assortment
of
macarons
ı
;
T
the
event
:
ˇ
The
customer
takes
a
slice
of
tarte
tatin
ı
;
P
event
:
ˇ
The
customer
does
not
take
any
dessert
ı
;
C
event
:
ˇ
The
customer
has
a
coffee
ı
and
C
the
opposite
event
of
C
.
1
Complete
the
probability
tree
below
:
2
Determine
the
probability
that
a
customer
chose
the
mac-aron
assortment
and
had
a
coffee.
3
An
assortment
of
macarons
is
sold
6
e
,
a
slice
of
tarte
tatin
is
sold
7
e
,
and
a
coffee
is
sold
2
e
.
Each
customer
orders
one
dish
(and
only
one)
at
a
single
price
of
18
e
,
and
does
not
order
more
than
one
dessert
or
more
than
one
coffee.
We
denote
X
the
random
variable
associating
each
cus-tomer
with
the
price
of
their
bill.
a
Determine
the
values
taken
by
the
random
variable
X
.
b
Draw
up
a
table
representing
the
probability
distribu-tion
of
the
random
variable
X
.
c
Determine
the
expected
value
of
the
random
variable
X
.
https://chingmath.fr
chapExoCorrec/7561
sacados/7561
chapExoCorrec/4822
sacados/4822
CCMCCTCCP
FGMCFGMC
RRSpRRSnRRSr
ESESESESESESES
E.4823
A
red
fruit
producer
offers
rasp-berries,
redcurrants
and
blueberries
for
direct
sale.
The
customer
can
buy
either
trays
of
fruit
for
tasting,
or
trays
of
fruit
for
jam.
The
grower
has
noticed
that,
among
his
customers,
9
sur
10
purchase
a
tray
of
fruit
for
jam.
Regardless
of
the
type
of
tray
purchased,
in
50
%
des
cases
the
customer
chooses
blueberry
for
fruit,
30
%
raspberries
in
the
other
cases,
redcurrant
is
chosen.
Note:
C
the
event
:
ˇ
le
customer
buys
a
punnet
of
fruit
at
con-fiture
ı
;
F
l
the
event
:
ˇ
the
customer
requests
raspberries
ı
;
G
the
event
:
ˇ
le
customer
requests
groseilles
ı
;
M
l’event
:
ˇ
le
customer
requests
myrtilles
ı
;
It
is
assumed
that
the
fruit
chosen
does
not
depend
on
the
type
of
tray
purchased
and
that
each
customer
buys
only
one
tray.
1
Complete
the
probability
tree
below
:
2
Determine
the
probability
of
C
∩
F
.
3
The
producer
sets
the
prices
of
his
trays
as
follows
:
The
base
price
of
a
punnet
of
fruit
for
jam
is
5
euros
and
that
of
a
punnet
of
fruit
for
eating
is
3
euros
;
If
the
selected
tray
contains
raspberries,
he
adds
1
eu-ros
to
the
price
of
the
tray;
If
the
selected
tray
contains
blueberries,
he
adds
2
eu-ros
to
the
price
of
the
tray;
If
the
selected
punnet
contains
redcurrants,
the
base
price
remains
unchanged.
We
note
X
the
random
variable
associating
each
cus-tomer
with
the
price
of
the
punnet
purchased.
a
What
are
the
values
taken
by
the
random
variable
X
?
b
Draw
up
a
table
representing
the
probability
distribu-tion
of
X
.
c
Determine
the
expected
value
of
the
random
variable
X
.
E.4837
A
sports
shop
offers
downhill
skis,
snowboards,
and
cross-country
skis
for
rent.
Its
rental
equipment
consists
of
60
%
downhill
skis,
with
the
remainder
divided
equally
between
snowboards
and
cross-country
skis.
After
each
day
of
rental,
the
equipment
is
checked
and
re-paired
if
necessary.
Regardless
of
the
type
of
equipment
rented,
30
%
of
the
equipment
requires
repair.
Each
piece
of
rented
equipment
is
listed
on
a
form
that
tracks
its
status.
A
form
is
selected
at
random.
The
following
events
are
considered
:
S
p
:
ˇ
The
card
is
for
a
pair
of
downhill
skis
ı
;
S
n
:
ˇ
The
record
is
for
a
snowboard
ı
;
S
r
:
ˇ
The
record
is
for
a
pair
of
touring
skis
ı
;
R
:
ˇ
The
equipment
needs
repair
ı
;
R
is
its
opposite
event.
All
results
for
the
first
four
questions
will
be
rounded
to
10
−
3
.
1
Copy
and
complete
the
probability
tree
below
:
2
a
Calculate
the
probability
that
the
card
drawn
con-cerns
a
pair
of
piste
skis
not
in
need
of
repair.
b
Calculate
P
S
p
∪
R
:
the
probability
that
the
card
drawn
concerns
a
pair
of
piste
skis
or
equipment
not
requiring
repair.
3
The
cost
of
renting
downhill
skis
or
a
snowboard
is
20
e
,
that
of
a
pair
of
touring
skis
is
15
e
.
In
the
event
of
repair,
an
additional
cost
of
15
e
est
will
be
charged.
Consider
the
random
variable
X
which
associates
the
as-sociated
billing
amount
with
a
plug.
a
Draw
a
table
representing
the
probability
distribution
of
the
random
variable
X
.
b
Determine
the
expectation
of
the
random
variable
X
.
13.
Bernoulli
test
E.7827
Consider
an
experiment
with
two
possible
outcomes
:
one
called
ˇ
suc-cess
ı
and
denoted
S
with
probabil-ity
0.4
;
the
other
called
ı
failure
ı
and
denoted
E
.
We
decide
to
repeat
this
same
ex-periment
three
times.
We
obtain
the
probability
tree
shown
oppo-site.
We
assume
that
these
repetitions
are
independent
of
each
other.
https://chingmath.fr
chapExoCorrec/4823
sacados/4823
FGMCFGMC
chapExoCorrec/4837
sacados/4837
RRSpRRSnRRSr
chapExoCorrec/7827
sacados/7827
ESESESESESESES
SESESESESESESE
SESESESESESESESESESESESESESESE
ESESESESESESESESESESESESESESES
ESESESESESESESESESESESESESESESESESESESESESESESESESESESESESESES
1
Complete
this
probability
tree?
2
a
How
many
paths
have
3
successes?
b
Give
the
probability
of
obtaining
three
successes
at
the
end
of
this
random
experiment.
3
a
How
many
paths
have
0
successes?
b
Give
the
probability
of
obtaining
no
successes
at
the
end
of
this
random
experiment.
4
a
How
many
paths
have
2
successes?
b
Give
the
probability
of
obtaining
exactly
two
successes
at
the
end
of
this
random
experiment?
E.4887
Here
are
the
choice
trees
associated
with
repeating
a
Bernoulli
test
3
and
4
times
respectively:
1
For
the
threefold
repetition
of
Bernoulli’s
test,
complete
the
table
below
:
Number
of
succès
0
1
2
3
Number
of
issues
2
a
For
the
fourfold
repetition
of
Bernoulli’s
test,
com-plete
the
table
below
:
Number
of
succès
0
1
2
3
4
Number
of
issues
b
Is
there
a
method
for
obtaining
the
second
table
from
the
first?
E.4886
In
a
game
arising
from
a
random
exper-iment,
only
two
outcomes
are
considered
:
success
(
S
)
at
this
game
and
failure
(
E
)
.
The
probability
of
success
is
0.15
.
Part
A
:
successive,
independent
repetition
of
4
games
Here
is
the
choice
tree
corresponding
to
this
repetition
of
ex-periments
;
1
Determine
the
probability
of
the
event
A
:
ˇ
The
player
won
exactly
3
fois
ı
2
Determine
the
probability
of
the
event
B
:
ˇ
The
player
won
exactly
2
fois
ı
Part
B:
successive
and
independent
repetition
of
5
games
Here’s
the
choice
tree
corresponding
to
this
game:
3
Determine
the
probability
of
the
event
C
:
ˇ
The
player
won
exactly
3
fois
ı.
https://chingmath.fr
chapExoCorrec/4887
sacados/4887
SESESESESESESE
SESESESESESESESESESESESESESESE
chapExoCorrec/4886
sacados/4886
ESESESESESESESESESESESESESESES
ESESESESESESESESESESESESESESESESESESESESESESESESESESESESESESES
PFPFPFPFPFPFPFPFPFPFPFPFPFPFPF
SESESESESESESESESESESESESESESE
E.389
1
A
player
flips
an
unbalanced
coin
with
a
probability
of
0
;
63
of
landing
on
heads.
What
is
the
probability
of
landing
on
tails?
We
want
to
examine
certain
outcomes
resulting
from
four
tosses
of
this
coin.
We
assume
that
these
tosses
are
indepen-dent
of
one
another.
Note:
The
elementary
events
P
-
P
-
F
-
P
and
P
-
F
-
P
-
P
are
different
outcomes
of
this
random
experiment,
but
each
of
them
results
in
the
same
number
of
heads
and
tails.
2
a
How
many
outcomes
correspond
to
getting
3
heads
and
1
tails?
b
What
is
the
probability
of
an
outcome
containing
3
heads
and
1
tails?
c
Use
this
to
determine
the
probability
of
getting
3
heads
during
this
experiment.
3
a
Which
of
the
following
calculations
represents
the
probability
of
a
roll
with
exactly
2
heads
:
(1
−
0
;
63)
2
;
0
;
63
3
×
(1
−
0
;
63)
0
;
63
2
×
(1
−
0
;
63)
2
;
0
;
63
×
(1
−
0
;
63)
3
b
Determine
the
probability
of
getting
2
heads
during
this
roll.
E.4911
1
Consider
the
choice
tree
below
from
the
fourfold
repeti-tion
of
a
Bernoulli
trial:
Determine
the
binomial
coefficients
below
:
a
4
2
b
4
3
2
Using
the
calculator,
determine
the
value
of
the
following
binomial
coefficients
:
a
5
3
a
12
5
a
8
6
a
7
2
14.
Binomial
law
E.7830
A
player
has
a
balanced
cubic
die
whose
faces
are
numbered
from
1
to
6
.
On
each
throw,
he
wins
if
he
gets
2
,
3
,
4
,
5
or
6
;
he
loses
if
he
gets
1
.
A
game
consists
of
5
successive,
independent
throws
of
the
die.
Determine
the
exact
probability
that
the
player
will
lose
3
times
during
a
game,
then
its
value
rounded
to
the
tenth.
E.7831
Consider
a
random
variable
X
following
the
binomial
distribution
with
parameters
n
=15
and
p
=0.63
.
1
Using
a
calculator,
determine
the
following
binomial
co-efficients
:
a
15
13
b
15
14
c
15
15
2
Using
a
calculator,
give
the
value
rounded
to
the
nearest
10
−
4
of
the
following
probabilities
:
a
P
X
=13
b
P
X
=14
c
P
X
=15
3
Deduce
the
value,
rounded
to
the
nearest
10
−
4
,
of
the
probability
of
event
X
12
.
E.4938
Let
X
be
a
random
variable
following
a
binomial
distribution
with
parameters
n
=35
and
p
=0.34
.
Determine
the
exact
value
and
then
the
value
rounded
to
10
−
5
of
each
of
the
following
probabilities
:
a
P
X
=5
b
P
X
=10
c
P
X
=25
E.4926
Consider
a
random
variable
X
following
the
binomial
distribution
with
parameters
n
=15
and
p
=0.63
.
We
will
give
the
exact
probability
of
each
of
the
probabilities
requested.
1
Determine
the
following
probabilities
:
a
P
X
=0
b
P
X
=1
c
P
X
=5
2
Give
the
probability
of
event
X
14
.
https://chingmath.fr
chapExoCorrec/389
sacados/389
PFPFPFPFPFPFPFPFPFPFPFPFPFPFPF
chapExoCorrec/4911
sacados/4911
SESESESESESESESESESESESESESESE
chapExoCorrec/7830
sacados/7830
chapExoCorrec/7831
sacados/7831
chapExoCorrec/4938
sacados/4938
chapExoCorrec/4926
sacados/4926
0123450,10,20,30,4
3XV2F2F2FV2V1F1F1FF2V1F1F1FF2V1F1F1FFV2V1F1F1FV1V0F0F0FF1V0F0F0FF1V0F0F0FFF2V1F1F1FV1V0F0F0FF1V0F0F0FF1V0F0F0FFF2V1F1F1FV1V0F0F0FF1V0F0F0FF1V0F0F0FFF
1414143XV342FV34142V341FFV3414142V341FV34141V340FFF
E.4928
A
random
variable
X
is
assumed
to
fol-low
a
binomial
distribution
with
parameters
n
=5
and
p
=0.6
.
1
Using
a
calculator,
draw
up
a
table
representing
the
law
of
the
variable
X
with
probabilities
rounded
to
the
near-est
thousandth.
2
Deduce
the
following
probabilities
rounded
to
the
hun-dredth
:
a
P
X
1
b
P
X
>
1
E.4930
1
Consider
the
random
variable
X
following
a
binomial
dis-tribution
with
parameters
n
=5
and
p
=0.5
.
a
Using
a
calculator
and
rounding
values
to
10
−
4
,
draw
up
a
table
showing
the
probability
distribution
of
the
random
variable
X
.
b
Draw
the
bar
chart
representing
the
law
of
the
random
variable
X
.
2
Consider
the
random
variable
X
following
a
binomial
dis-tribution
with
parameters
n
=5
and
p
=0.37
.
a
Using
the
calculator
and
rounding
values
to
10
−
4
,
draw
up
a
table
showing
the
probability
distribution
of
the
random
variable
X
.
b
Draw
the
bar
chart
representing
the
law
of
the
random
variable
X
.
E.7385
Consider
a
multiple-choice
questionnaire
consisting
of
3
questions
each
offering
4
answers,
only
one
of
which
is
correct.
We
create
a
random
experiment
by
asking
participants
to
ran-domly
answer
the
questions
proposed
in
the
form.
This
situation
is
represented
by
the
choice
tree
below
:
For
each
elementary
event,
we
associate
the
random
variable
X
with
the
number
of
correct
answers.
1
Give
the
probability
law
of
the
random
variable
X
.
For
each
question
in
the
M.C.Q.,
the
probability
of
a
correct
answer
is
1
4
and
a
wrong
answer
is
3
4
.
The
choice
tree
is
simplified
by
the
probability
tree
below
:
2
a
Using
this
probability
tree,
what
calculation
finds
the
values
of
the
probabilities
:
P
X
=0
;
P
X
=3
b
What
method
can
be
one
apply
to
quickly
obtain
the
values
of
P
X
=1
and
P
X
=2
?
E.7487
Ten
people
apply
for
a
job
in
the
company.
Their
applications
are
studied
independently
of
each
other.
We
denote
by
X
the
random
variable
giving
the
number
of
people
recruited
among
the
10
people.
We
know
38
%
of
the
applicants
have
been
recruited.
1
Justify
that
X
follows
a
binomial
distribution
with
pa-rameters
n
=10
and
p
=0.38
.
2
Calculate
the
probability
that
at
least
one
of
the
ten
peo-ple
will
be
recruited.
The
exact
value
and
then
a
value
of
the
result
rounded
to
10
−
3
will
be
given.
https://chingmath.fr
chapExoCorrec/4928
sacados/4928
chapExoCorrec/4930
sacados/4930
0123450,10,20,30,4
0123450,10,20,30,4
chapExoCorrec/7385
sacados/7385
3XV2F2F2FV2V1F1F1FF2V1F1F1FF2V1F1F1FFV2V1F1F1FV1V0F0F0FF1V0F0F0FF1V0F0F0FFF2V1F1F1FV1V0F0F0FF1V0F0F0FF1V0F0F0FFF2V1F1F1FV1V0F0F0FF1V0F0F0FF1V0F0F0FFF
1414143XV342FV34142V341FFV3414142V341FV34141V340FFF
chapExoCorrec/7487
sacados/7487
Extrait Antilles-Guyanes
Juin 2014
Représentation 1
Représentation 2
E.7829
Let
X
follow
a
binomial
distribution
with
parameters
15
and
0.35
.
C’est-à-dire
:
X∼B
(15
;
0.35)
Determine
the
exact
value,
then
the
value
rounded
to
the
thousandth
of
the
following
probabilities
:
a
P
X
=5
b
P
X
=7
c
P
X
=9
E.7640
By
choosing
a
pupil
at
random
from
among
those
registered
for
half-board,
we
know
that
the
probability
of
the
chosen
pupil
being
satisfied
with
half-board
is
0.675
.
Each
time,
a
group
of
4
students
is
interviewed.
We
denote
X
the
random
variable
equal
to
the
number
of
stu-dents
declaring
themselves
satisfied
with
the
quality
of
the
meals.
As
the
number
of
students
is
sufficiently
large,
X
is
considered
to
follow
a
binomial
distribution.
Results
will
be
rounded
to
the
nearest
thousandth.
1
Specify
the
parameters
of
this
binomial
distribution.
2
Calculate
the
probability
of
the
event
A
:
ˇ
the
four
stu-dents
are
satisfied
with
the
quality
of
repas
ı.
3
Describe
in
a
sentence
the
event
A
and
calculate
its
prob-ability.
E.4888
Consider
an
urn
containing
6
red
balls
and
4
blue
balls
indistinguishable
by
touch.
1
One
ball
is
drawn
at
random
from
this
urn.
What
is
the
probability
of
getting
a
red
ball?
We
decide
to
draw
three
balls
in
succession.
Each
time,
the
ball
is
put
back
into
the
urn
(the
draw
is
said
to
be
with
de-livery)
.
2
Consider
the
Bernoulli
scheme
resulting
from
this
repeti-tion,
where
success
is
associated
with
the
event
ˇ
having
drawn
a
ball
rouge
ı
a
What
are
the
parameters
of
this
Bernoulli
scheme?
b
Construct
the
tree
representing
this
situation.
c
How
many
elementary
events
realize
the
event
:
ˇ
having
drawn
2
balls
rouges
ı
E.4909
In
this
exercise,
all
results
will
be
rounded
to
the
nearest
10
−
3
.
In
a
city,
a
survey
shows
that
87
%
of
the
inhabitants
own
a
cell
phone.
Three
inhabitants
are
chosen
successively,
at
random
and
in-dependently.
Note
X
the
number
of
people
selected
who
own
a
cell
phone.
1
What
values
can
the
random
variable
X
take?
The
random
variable
X
is
assumed
to
follow
a
binomial
dis-tribution
with
parameters
3
and
0.87
:
2
Give,
in
a
table,
the
probability
distribution
of
the
ran-dom
variable
X
?
3
What
is
the
probability
that
at
least
two
of
his
three
people
own
a
cell
phone?
E.4939
Let
X
be
a
random
variable
following
a
binomial
distribution
with
parameters
n
=35
and
p
=0.35
.
Using
the
calculator,
determine
the
following
probabilities
rounded
to
the
nearest
thousandth
:
a
P
X
5
b
P
X
10
c
P
X
20
E.4937
Of
the
two
representations
below
and
without
justification,
give
the
one
that
represents
the
law
of
a
random
variable
X
following
the
binomial
law
with
param-eters
n
=10
and
p
=0.3
:
E.4929
A
random
variable
X
is
assumed
to
follow
a
binomial
distribution
with
parameters
n
=8
and
p
=0.37
.
Determine
the
probability
value
P
3
X
7
rounded
to
the
nearest
hundredth.
E.4927
A
vaccine
is
being
tested
on
a
popula-tion
of
100
individuals.
30
of
them
react
to
this
vaccine
with
high
fevers.
Each
test
phase
is
carried
out
on
a
group
of
5
in-dividuals
chosen
at
random
and
independently
between
each
test.
Let
us
note
X
the
random
variable
that
associates
with
each
test
phase
the
number
of
individuals
who
had
a
reaction
with
high
fevers.
1
Justify
that
the
random
variable
X
follows
a
binomial
distribution
whose
parameter
values
will
be
specified.
2
Determine
the
probability
that
2
individuals
reacted
to
the
vaccine
with
fever
over
a
test
phase.
3
Over
a
test
phase,
what
is
the
probability
that
at
least
4
individuals
have
reacted
with
fever.
https://chingmath.fr
chapExoCorrec/7829
sacados/7829
chapExoCorrec/7640
sacados/7640
chapExoCorrec/4888
sacados/4888
chapExoCorrec/4909
sacados/4909
chapExoCorrec/4939
sacados/4939
chapExoCorrec/4937
sacados/4937
Représentation 1
Représentation 2
chapExoCorrec/4929
sacados/4929
chapExoCorrec/4927
sacados/4927