You have a delicious round birthday cake. How many equal-sized pieces can you cut the cake into by making only three straight slices with a knife and without moving any of the pieces?

You are in an empty room with a glass of water. The glass is a right cylinder that looks like it is about half-full, but you are not quite sure ...

In front of you are three closed metal boxes. One is labeled "Nuts," one is labeled "Bolts," and one is labeled ...