There are N players in a tennis tournament. Assuming the initial pairings are done randomly, what are the odds that a certain pair will play each other?
(In reply to My Answer
This is wrong. Imagine there are three players: 1, 2 and 3 -- 1 will play 2, and the winner will play 3.
If you are at #1, and the other at #2 (or you at #2 and the other at #1) you'll meet with certainty.
If you are at #1 or #2, and the other at #3 (or you at #3 and the other at #1 or #2) you'll meet with 50% probability.
Then, in 2 out of 6 chances it's a sure thing, and in 4 out of 6, a 50%
thing -- summing everything, the chances are 2 out of 3 you'll meet...
and this agrees with Charlie and e.g., and not with Pcbouhid's result