Answer:
Given six presidents to arrange in chronological order, in this case, Permutations will work better not combination.
Explanation:
In permutations, the order of the element is important. It is the arrangement of the set in a linear order. When the order of a selection is a factor, it becomes permutation.
The first president in this list can be chosen in six different ways, like wise the second president can be chosen in five ways. There are now five presidents left, The third president in the list can be chosen in four different ways (remaining three presidents), the fifth president can also be chosen in two ways and finally the sixth president in one way.
Hence, 6.5.4.3.2.1 = 720, In the above arrangement, only one is correct, Therefore the probability is 1/720.
