A fish tank contains eight algae-eaters, five catfish, and six tilapia fish. A storekeeper randomly selects two fish (one after another without replacement) from the tank for a customer. Find the probability that both fish selected are catfish.
+115 The probability of the first fish being a catfish is 5 catfish out of 19 total fish \(\Rightarrow \frac{5}{19}\)
The probability of the second fish being a catfish is 4 catfish out of 18 total fish \(\Rightarrow \frac{4}{18} \Rightarrow \frac{2}{9}\)
The total probability is \(\frac{5}{19} \cdot \frac{2}{9} = \frac{10}{171}\)
