Question

If Brazil has a total of 150 bird species and you happen to catch two species in an observational experiment using mist nets, what is the total number of possible combinations of species that you captured

Answer 1

The total number of possible combinations of species that you captured is 11,175.

Explanation:

The order that you captured the species is not important. For example, capturing a bird of specie A then a bird of specie B is the same outcomes as capturing a bird of specie B then a bird of specie A. So the combinations formula is used to solve this question.

Combinations formula:

`C_(n,x)` is the number of different combinations of x objects from a set of n elements, given by the following formula.

`C_(n,x) = (n!)/(x!(n-x)!)`

In this problem, we have that:

Combinations of 2 species from a set of 150. So

`C_(150,2) = (150!)/(2!148!) = 11,175`

The total number of possible combinations of species that you captured is 11,175.