If Brazil has a total of 130 bird species and you happen to catch three species
ID: 166141 • Letter: I
Question
If Brazil has a total of 130 bird species and you happen to catch three species in an observational experiment using mist nets, what is the total number of possible combinations of species that you captured? A special note for this situation The order does not matter (catching species A, species B, and species C is not different from catching species B, C, and A), so the appropriate formula to use is n!/k!(n - k)! Where n is the possible number of objects, species, etc., and k is the number that is observed, caught, etc. Adding the (1/k!) allows differently-ordered objects to count only once; therefore; the formula will reflect that catching species A, B and C is the same combination as both C, B, A, and B, A, C.Explanation / Answer
The given formula is for number of possible combinations of k objects from a set of n objects.
n= Possible number of objects=Total bird species=130
k=no. of species to be caught=3
so, Total number of possible combination of species captured
=nCk
= 130C3
=130!/3!*(130-3)!
=130*129*128*127! / 3*2*1 *127!
=130*129*128/3*2
=357760
So total of 357760 possible combination of species one can capture.