Students in a class were surveyed about the number of children in their families. The results of the survey are shown in the table.

\begin{tabular}{|c|c|}
\hline
\begin{tabular}{c}
Number of Children \\
in Family
\end{tabular} & \begin{tabular}{c}
Number of \\
Surveys
\end{tabular} \\
\hline one & 9 \\
\hline two & 18 \\
\hline three & 22 \\
\hline four & 8 \\
\hline five or more & 3 \\
\hline
\end{tabular}

Two surveys are chosen at random from the group of surveys. After the first survey is chosen, it is returned to the stack and can be chosen a second time. What is the probability that the first survey chosen indicates four children in the family and the second survey indicates one child in the family?

A. [tex]$\frac{1}{50}$[/tex]

B. [tex]$\frac{2}{15}$[/tex]

C. [tex]$\frac{3}{20}$[/tex]

D. [tex]$\frac{17}{60}$[/tex]



Answer :

To find the probability that the first survey chosen indicates four children in the family and the second survey indicates one child in the family, we can break it down into a few steps:

1. Calculate the total number of surveys:
The total number of surveys is the sum of all the surveys given in the table.

[tex]\[ \text{Total surveys} = 9 + 18 + 22 + 8 + 3 = 60 \][/tex]

2. Calculate the probability of choosing a survey indicating four children in the family (first choice):
The number of surveys indicating four children is 8.

[tex]\[ \text{Probability (first choice, four children)} = \frac{8}{60} = \frac{2}{15} \approx 0.133 \][/tex]

3. Calculate the probability of choosing a survey indicating one child in the family (second choice):
Since the survey is replaced after the first selection, the total number of surveys remains the same (60). The number of surveys indicating one child is 9.

[tex]\[ \text{Probability (second choice, one child)} = \frac{9}{60} = \frac{3}{20} = 0.15 \][/tex]

4. Multiply the probabilities of these two independent events:
Since each choice is independent (the survey is replaced), we multiply the probabilities of the two events.

[tex]\[ \text{Probability (first four children, then one child)} = \left(\frac{8}{60}\right) \times \left(\frac{9}{60}\right) = \frac{2}{15} \times \frac{3}{20} = \frac{6}{300} = \frac{1}{50} = 0.02 \][/tex]

So, the probability that the first survey chosen indicates four children in the family and the second survey indicates one child in the family is [tex]\(\frac{1}{50}\)[/tex], which corresponds to approximately [tex]\(0.02\)[/tex].

Therefore, the correct answer is:

[tex]\[ \boxed{\frac{1}{50}} \][/tex]