If a bottle and a cork cost a dollar and a nickel, and the bottle costs a dollar more than the cork, how much does the cork cost?
[toggle title="What's the answer?"]Most people guess 5¢, but $1 more than 5¢ is $1.05, and if the bottle cost $1.05, the bottle and the cork would be $1.10, not $1.05. The cork actually costs 2½¢ and the bottle costs a dollar more, or $1 and 2½¢, making the total $1.05.[/toggle]