Answer:

Step-by-step explanation:
First, find the probability of him pulling out a book.
There are 11 objects in total, and there are 4 books.
So, the probability of pulling out a book is 
Next, find the probability of him pulling out a DVD after.
Since a book was taken out, there are only 10 objects left. There are 5 DVDs.
So, the probability of pulling out a DVD is
, or simplified to 
To find the probability that this happens in order, multiply the probabilities:
x 
= 
So, the probability is 
Answer:
According to the sample data, we can claim that the current satisfaction rate is different from last year's.
Step-by-step explanation:
The explanation is in the picture.
Answer:
It's the first one
Step-by-step explanation:
Because 2M means you are multiplying all the values of M with 2
Answer:
108 pens
Step-by-step explanation:
48/4=x/9
4x=432
x=108
Answer:
(a)
and
are indeed mutually-exclusive.
(b)
, whereas
.
(c)
.
(d)
, whereas 
Step-by-step explanation:
<h3>(a)</h3>
means that it is impossible for events
and
to happen at the same time. Therefore, event
and
are mutually-exclusive.
<h3>(b)</h3>
By the definition of conditional probability:
.
Rearrange to obtain:
.
Similarly:
.
<h3>(c)</h3>
Note that:
.
In other words,
and
are collectively-exhaustive. Since
and
are collectively-exhaustive and mutually-exclusive at the same time:
.
<h3>(d)</h3>
By Bayes' Theorem:
.
Similarly:
.