Jane Street

Interview Question

Trader Interview
Jane Street

There are infinitely many cards numbered 1 to 5. You construct a deck by selecting any composition of these cards. A player guesses a value between 1 and 5 and draws a card at random from the deck. If they guessed the correct number, they receive a payout equal to that value; otherwise, they get nothing. What composition of the deck minimizes the player's expected payout?

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