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2004 AMC 12A Problem 7

Problem 7 of 25Easier

A game is played with tokens according to the following rule. In each round, the player with the most tokens gives one token to each of the other players and also places one token into a discard pile. The game ends when some player runs out of tokens. Players A,A, B,B, and CC start with 15,15, 14,14, and 1313 tokens, respectively. How many rounds will there be in the game?

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Solution

After three rounds the players A,A, B,B, and CC have 14,14, 13,13, and 1212 tokens, respectively. Every subsequent three rounds reduces each player’s supply by one token. After 3636 rounds they have 3,3, 2,2, and 11 tokens. In the 3737th round player A,A, who has the most, gives away all three of their tokens and runs out, ending the game. Thus, the correct answer is B.

More practice

Concepts: process simulation · invariant

Problem text and solution from the LIVE past-contest archive. See also the AoPS wiki page for community solutions.