Representated in a table the 3 kinds of combinations of 2

 

The table when the order of the elements aren't important and the second when the order of the elements are important

So we have 3 possibilities:

1 - I that is the 1st table the two doesn't accet combination by istself and the order isn't important so 1-2 and 2-1 are the same type candidates for president but if I sai that wasn't a tie and have the best colocated and the second, but if isn't the case is the 1st table.

2 - Possibility is the order matters but one can match with itself so we gonna have the 2nd table without the yellow cross line.

3 - The elements can be repeated so 1 can be combined with one

We gonna have that combinations for that elements 

Where n is the number of elements:

n*(n-1)/2 when the number can be combined by itself an when the order no matters and 1-2 is equal 2-1

n*(n-1) when the order is important and 1-2 is diferent than 2-1

n*n and now is the complete "putaria" the number can combine with itself and the order matters

But this are combinations for 2 so how many possibles ways I can combine 2 candidates, how can 2 teams of sports, had other combinations.

And now who can save us, is the reading of the text of the mathematical problem that you gonna see what is the formula to use.

Rute Bezerra de Menezes Gondim