Questions: A pet store has 9 puppies, including 4 poodles, 4 terriers, and 1 retriever. Rebecka and Aaron, in that order, each select one puppy at random without replacement. Find the probability that Aaron selects a retriever, given Rebecka selects a retriever.
Transcript text: A pet store has 9 puppies, including 4 poodles, 4 terriers, and 1 retriever. Rebecka and Aaron, in that order, each select one puppy at random without replacement. Find the probability that Aaron selects a retriever, given Rebecka selects a retriever.
The probability is $\square$
Solution
Solution Steps
Step 1: Calculate \( P(B) \)
To find the probability that Rebecka selects a retriever, we note that there is 1 retriever among a total of 9 puppies. Thus, the probability \( P(B) \) is calculated as:
\[
P(B) = \frac{1}{9} \approx 0.1111
\]
Step 2: Calculate \( P(A \cap B) \)
Next, we determine the probability that both Rebecka and Aaron select the retriever. If Rebecka selects the retriever, there are no retrievers left for Aaron to select. Therefore, the probability \( P(A \cap B) \) is:
\[
P(A \cap B) = 0
\]
Step 3: Calculate \( P(A | B) \)
Finally, we compute the conditional probability that Aaron selects a retriever given that Rebecka has selected a retriever. Using the formula for conditional probability:
\[
P(A | B) = \frac{P(A \cap B)}{P(B)}
\]
Substituting the values we found:
\[
P(A | B) = \frac{0}{\frac{1}{9}} = 0
\]
Final Answer
The probability that Aaron selects a retriever, given that Rebecka selects a retriever, is