Using one or more addition, subtraction, multiplication or division operations, what formula using the numbers 3, 3, 8 and 8 equals 24?

This Roman numeral equation is wrong, but you can fix it without changing any of the elements of the equation. How is this possible?

I + XI = X

If a piece of rope was tightly wrapped around the earth and you added 3 feet to its length, how high could you uniformly raise it from the earth’s surface?

A man is leaving on a business trip and stops by his office on the way to the airport. The night watchman stops him and says, “Sir, don’t take that flight. I had a dream last night that your plane would crash and everyone would die!” The business man cancels his trip and sure enough, the plane crashes, killing all the passengers. The man gives his watchman a $10,000 reward for saving his life, then fires him. Why?

A full glass of water with a single ice cube sits on a table. When the ice has completely melted, will the level of the water have increased, decreased or remain unchanged?