Considering the definition of probability, the correct answer is third option: the approximate probability of a moth being brown and yellow respectively is 33% and 21%
Probability is the greater or lesser possibility of a certain event occurring.
In other words, probability establishes a relationship between the number of favorable events and the total number of possible events.
Then, the probability of any event A is defined as the quotient between the number of favorable cases (number of cases in which event A may or may not occur) and the total number of possible cases. This is called Laplace's Law.
In this case, you know that in a moth population, 48 are brown, 30 are yellow, and 67 are black. So, the total number of possible cases is calculated as:
total number of possible cases= 48 + 30 + 67= 145
The number of favorable cases for a moth to be brown is: 48
Then the probability that a moth is brown is calculated as:
= 0.33= 33%
On the other side, the number of favorable cases for a moth to be yellow is: 30
Then the probability that a moth is yellow is calculated as:
= 0.21= 21%
In summary, the correct answer is third option: the approximate probability of a moth being brown and yellow respectively is 33% and 21%
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