Answer to Puzzle #2
Since oil floats on top of vinegar, Rita removed three drops of oil from the surface. She closed the bottle, inverted it and when the oil rose to the top, she simply loosened the lid enough to allow two drops of vinegar to fall out.
There is a town in Texas where 5% of all the people living there have unlisted phone numbers. If you selected 100 names at random from the town's phone directory, on average, how many of these people would have unlisted phone numbers?