Use the table to answer the question.

Train Arrival
Age Group Prefers Fiction Prefers Nonfiction Total
20 to 30 years old 12 3 15
31 to 40 years old 24 6 30
Total 36 9 45
Let event A
be someone who is 31 to 40 years old and event B
represent someone who prefers fiction. Find P(A and B)
and determine if the two events are independent.

(1 point)
Responses

P(A and B)=645
and shows that the two events are independent.
upper P left parenthesis upper A and upper B right parenthesis equals Start Fraction 6 over 45 End Fraction and shows that the two events are independent.

P(A and B)=2445
but does not indicate that the two events are independent.
upper P left parenthesis upper A and upper B right parenthesis equals Start Fraction 24 over 45 End Fraction but does not indicate that the two events are independent.

P(A and B)=2445
and shows that the two events are independent.
upper P left parenthesis upper A and upper B right parenthesis equals Start Fraction 24 over 45 End Fraction and shows that the two events are independent.

P(A and B)=6645
and shows that the two events are independent.

1 answer

To find \( P(A \text{ and } B) \), we first identify the number of people who are both in the age group of 31 to 40 years old (event A) and prefer fiction (event B).

From the table provided:

  • The number of people aged 31 to 40 who prefer fiction is 24.
  • The total number of people surveyed is 45.

Thus, we can calculate \( P(A \text{ and } B) \) as follows:

\[ P(A \text{ and } B) = \frac{\text{Number of people who are 31 to 40 and prefer fiction}}{\text{Total number of people}} = \frac{24}{45} \]

Next, we need to determine if events A and B are independent. Two events A and B are independent if:

\[ P(A \text{ and } B) = P(A) \times P(B) \]

First, we calculate \( P(A) \) and \( P(B) \):

  1. Calculate \( P(A) \):

    • Total people aged 31 to 40 = 30.
    • Therefore, \( P(A) = \frac{30}{45} \).
  2. Calculate \( P(B) \):

    • Total people who prefer fiction = 36.
    • Therefore, \( P(B) = \frac{36}{45} \).

Now we can compute \( P(A) \times P(B) \):

\[ P(A) \times P(B) = \left(\frac{30}{45}\right) \times \left(\frac{36}{45}\right) = \frac{30 \times 36}{45 \times 45} = \frac{1080}{2025} \]

Next, we simplify the fractions where necessary:

  1. Compare \( P(A \text{ and } B) \) with \( P(A) \times P(B) \):

\[ P(A \text{ and } B) = \frac{24}{45} \] \[ P(A) \times P(B) = \frac{1080}{2025} \]

Since \( \frac{24}{45} \) does not equal \( \frac{1080}{2025} \), events A and B are not independent.

So the choice from the options is:

\[ P(A \text{ and } B) = \frac{24}{45} \text{ but does not indicate that the two events are independent.} \]

Final Choice:

"P(A and B) = 24/45 but does not indicate that the two events are independent."