Gopi buys a fish from a shop for his aquarium. The shopkeeper takes out one fish at random from a tank containing 5 male fish and 8 female fish (see Fig. 14.4). What is the probability that the fish taken out is a male fish?
To determine the probability, we first calculate the total number of possible outcomes. The tank contains 5 male fish and 8 female fish. Thus, the total number of fish is calculated as . Since the fish is taken out at random, there are 13 equally likely outcomes.
Next, we identify the number of favourable outcomes. The event in question is taking out a male fish. There are exactly 5 male fish in the tank, so the number of favourable outcomes is 5. The probability is calculated using the formula: Probability =
Substituting the values:
Therefore, the probability that the fish taken out is a male fish is .
Explanation
This question is solved using the classical definition of probability found in the provided context (specifically referencing the logic in Example 7 and Example 12). The total number of outcomes represents the total population of fish (5 male + 8 female = 13). The favourable outcomes correspond specifically to the count of male fish (5). The probability is the ratio of favourable outcomes to total outcomes.
Solution Steps
Step 1: Calculate the total number of fish in the tank by adding male and female fish: .
Step 2: Identify the number of favourable outcomes (male fish) which is 5.
Step 3: Apply the probability formula: .