The answer is very nice! With the worker's village modification above, I would suggest the puzzle to be formulated as:
.....
knowing there are at least 2 treasures and no coppers in your deck and discard pile, you now know you can win by getting the two Provinces, regardless what other cards are and how they are arranged.
What are your remaining 3 cards in hand?
(By the way, saying there is exactly one Silver and exactly 10 cards in the deck, without mentioning anything about the discard pile is not a good way to formulate the puzzle. Your answer is neither constrained or dependent on these conditions. While sometimes a puzzle needs some distractions, this is just going to lead people to think in the wrong direction and wastes lots of their time.)