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AIME 2025b Problem 8

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From an unlimited supply of 11-cent coins, 1010-cent coins, and 2525-cent coins, Silas wants to find a collection of coins that has a total value of NN cents, where NN is a positive integer. He uses the so-called greedy algorithm\textit{greedy algorithm}, successively choosing the coin of greatest value that does not cause the value of his collection to exceed NN. For example, to get 4242 cents, Silas will choose a 2525-cent coin, then a 1010-cent coin, then 77 11-cent coins. However, this collection of 99 coins uses more coins than necessary to get a total of 4242 cents; indeed, choosing 44 1010-cent coins and 22 11-cent coins achieves the same total value with only 66 coins. In general, the greedy algorithm succeeds for a given NN if no other collection of 11-cent, 1010-cent, and 2525-cent coins gives a total value of NN cents using strictly fewer coins than the collection given by the greedy algorithm. Find the number of values of NN between 11 and 10001000 inclusive for which the greedy algorithm succeeds.

Dataset text AIME 1983 to 2026. Quoted with source.

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