Stone piles
There are 100 stones, Ashley and Bob are playing a game. Each turn they take stones from the pile. The last one who take the stones wins the game.
First turn goes to Ashley, she takes 3 stone. Then Bob takes 2 stones. If the next turn Ashley takes 1 stone, how many stones should Bob takes to win the game?
Note : each turn they must take 1, 2, or 3 stones and cannot pass.
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1 solution
From 100 stones, Ashley picks 3, then Bob picks 2, remaining stones is 95. The next turn Ashley picks 1 stone, so Bob should take 2 stones to make remaining stones is 92, and Bob will wins if he keeps the remaining stones divisible by 4 until the game ends.
The answer is 2