Game of Intelligence

A blonde is sitting next to a lawyer on an aeroplane who keeps asking her to play a game of intelligence with him. Eventually she agrees when he offers $50 when he can't answer a question and requests $5 when she can't answer a question. The lawyer starts, "how far is it to the moon?" Immediately the blonde hands him $5. Then she asks, "what has 5 legs when sleeping and 10 when awake?" The lawyer thinks for a long time and eventually gives up and hands her $50. "What was the answer?" he asks. The blonde hands him $5 without a word.