A taste test asks people from Texas and California which pasta they prefer, brand A or brand B. This table shows the results.

\begin{tabular}{|l|c|c|c|}
\hline & Brand A & Brand B & Total \\
\hline Texas & 80 & 45 & 125 \\
\hline California & 90 & 60 & 150 \\
\hline Total & 170 & 105 & 275 \\
\hline
\end{tabular}

A person is randomly selected from those tested. What is the probability that the person is from California, given that the person prefers brand A? Round your answer to two decimal places.

A. 0.55
B. 0.60
C. 0.62
D. 0.53



Answer :

Alright, let's solve this step-by-step.

First, let's organize the information given in the table:

[tex]\[ \begin{tabular}{|l|c|c|c|} \hline & \text{Brand A} & \text{Brand B} & \text{Total} \\ \hline \text{Texas} & 80 & 45 & 125 \\ \hline \text{California} & 90 & 60 & 150 \\ \hline \text{Total} & 170 & 105 & 275 \\ \hline \end{tabular} \][/tex]

The question asks for the probability that a person is from California, given that they prefer Brand A. This can be found using the conditional probability formula:

[tex]\[ P(\text{California} | \text{Brand A}) = \frac{P(\text{California and Brand A})}{P(\text{Brand A})} \][/tex]

We need the following pieces of information:
1. [tex]\( P(\text{California and Brand A}) \)[/tex]: the number of people from California who prefer Brand A.
2. [tex]\( P(\text{Brand A}) \)[/tex]: the total number of people who prefer Brand A.

From the table:
- The number of people from California who prefer Brand A is 90.
- The total number of people who prefer Brand A is 170.

Using these values in the conditional probability formula:

[tex]\[ P(\text{California} | \text{Brand A}) = \frac{90}{170} \][/tex]

Now, let's calculate this fraction:

[tex]\[ \frac{90}{170} \approx 0.5294 \][/tex]

We are asked to round the answer to two decimal places. So, rounding 0.5294 to two decimal places:

[tex]\[ 0.53 \][/tex]

Thus, the probability that a randomly selected person who prefers Brand A is from California is:

[tex]\(\boxed{0.53}\)[/tex]

So the correct answer is:
D. 0.53