A pack of cards consisting 10 red cards and 10 blue cards is shuffled, and the dealer deals out one card to you at a time. At any point, after seeing a number of cards, you may announce: "the next card will be red!" Devise a strategy for making your guess be the highest probability of getting a red card.
The highest probability would be 100%. As the cards are being dealt, count the blue ones.
After 10 blue cards have been dealt, then stop the deal and say "The next card will be red."
By the way, if you follow this strategy, your declaration will not be a guess.
.