Maths Olympiad Prep

Track / Stage 5 / 6 of 400 #606 of 1964

Problem 606

AIME late
Combinatorics Difficulty 5.0 Find the answer

## 40. Tennis Tournament

199 people have registered to participate in a tennis tournament. In the first round, pairs of opponents are selected by lottery. The same process is used to select pairs in the second, third, and all subsequent rounds. After each match, one of the two opponents is eliminated, and whenever the number of participants in the tournament is odd, one of them skips the current round.

Assume that in each match between two tennis players, a new can of balls is used. How many cans of balls will be needed for the entire tournament?

A number or a short expression. Spacing, $ signs and \frac vs / are all fine.

Official solution

40. After each match, one of the opponents is eliminated, and since 199 people are participating in the tournament, by the end, 198 athletes must be eliminated. Therefore, for the entire tournament, 198 boxes of balls will be needed.

Source: NuminaMath-1.5, licensed Apache-2.0. Statement and solution reproduced as published; topic, difficulty and ordering added by this site.