Unlisted Phone Number

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?




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No Solution

In 2007, a puzzle was released and $2 million prizes were offered for the first complete solution. The competition ended at noon on 31 December 2010, with no solution being found. Wiki