Enigma Number 1554

摘要

My little nephew and I play a simple guessing game using an ordinary pack of cards. In the first round we lay seven cards face down and he has to guess how many are red cards (a number between 0 and 7). Then, likewise, I have to guess how many are black, but I must choose my number so that the two guesses do not add up to 7 (so that at least one of us will be wrong). Then, on turning the cards over, my nephew earns 1 point for each red card plus a bonus of 10 points if his guess was correct and I earn 1 point for each black card plus a bonus of 10 pointsrnif my guess was correct. Then in the second round we repeat the exercise with six cards, then in subsequent rounds with five, four, three, two and one card.