Puzzle of the day

Question: You have 100 coins stacked in a pile, all facing the same way (either heads or tails). You can only flip a single coin at a time. Is it possible to flip exactly 50 coins to the opposite side?

Answer: Yes

Explanation: First, flip the top coin. This will change the facing of one coin. Then, flip every other coin thereafter. For example, flip coins 3, 5, 7, etc. This will flip a total of 50 coins to the opposite side.