Suppose there are 1.2 × 104 civilizations broadcasting radio signals in the Milky Way Galaxy right now.
Part A - On average, how many stars would we have to search before we would expect to hear a signal? Assume there are 500 billion stars in the galaxy.
Express your answer using two significant figures.
Part B - How does your answer change if there are only 110 civilizations instead of 1.2 × 104?
Express your answer using two significant figures.