Question

The two-way table shows the number of books of each type in Eliza's home ​what is the probability that a randomly selected reference book is hard cover

Answer 1

Answer:

Hence, the probability that a randomly selected reference book is a hardcover is:

                             0.4

Step-by-step explanation:

Let A denote the event that the book selected is a reference book.

and B denote the event that the book  is hardcover.

Let P denote the probability of an event.

We are asked to find:

                  P(B|A)

We know that:

$P(B|A)=\dfrac{P(A\bigcap B)}{P(A)}$

From the table we have:

$P(A)=\dfrac{25}{60}=\dfrac{5}{12}$

and

$P(A\bigcap B)=\dfrac{10}{60}=\dfrac{1}{6}$

Hence, we have:

$P(B|A)=\dfrac{\dfrac{1}{6}}{\dfrac{5}{12}}\\\\\\P(B|A)=\dfrac{2}{5}\\\\\\P(B|A)=0.4$

           Hence, the answer is:

                 0.4

Answer 2

Answer:

B. 0.4

Step-by-step explanation:

Use the definition of the probability

$Pr=\dfrac{\text{Number of all favorable outcomes}}{\text{Number of all possible outcomes}}$

You have to find the probability that a randomly selected reference book is hard cover. Hence, from the table

• Number of all possible outcomes = Number of Reference books = 25
• Number of all favorable outcomes = Number of Hardcover Reference books = 10

So, the probability is

$Pr=\dfrac{10}{25}=\dfrac{40}{100}=0.4$