A man has ten candles. He blows out three. How many candles are left?
Answer: 3 candles.
The trick is to think about what happens over time. The seven candles that remain lit will continue burning and eventually melt away. The three candles that were blown out stop burning and therefore remain.
If you interpret the question as asking how many physical candles are present immediately after he blows them out, all ten are still there. But in the classic version of this riddle, “left” means the candles that remain after the others burn down.
Under that intended interpretation, the answer is 3 candles.
