Its a knockout

20 players enter a knockout tennis competition.

1. How many byes are there in the first round?

2. How many matches are there in total?

3. N players enter a knockout competion. How many matches are there in total?

N-1 matches

19 matches, # of byes depends on how byes are handled.

One could try for mimimal byes and there would be 2 byes, in the 3rd and 4th rounds respectively.

One could also place all byes in the first round, in which case there would be 12, with 4 matches to kick this thing off.

It does not matter how many byes you have or in what round.

You always need N-1 results to eliminate N-1 players to leave one champ.