In the city of Brain Teasers, 5% of people do not list their phone numbers. Now if we select random 100 people from the phone directory, then how many people selected will have unlisted phone numbers?
What is the four-digit number in which the first digit is one-third the second, the third is the sum of the first two, and the last is three times the second?
How many points are there on the globe where, by walking one mile south, then one mile east and then one mile north, you would reach the place where you started?