[ladygreek]

Originally Posted by Drolefille

And a few riddles:
1.In a large western city, 80% of the phone numbers are listed, 20% of the phone numbers are businesses, and 20% of the phone numbers start with the numeral "2". If you were to take a random sample of 1000 phone numbers from the city's phone book, how many numbers would you expect to be unlisted, non-business phone numbers that start with a numeral other than "2"?

None. If they are unlisted they wouldn't be in the phone book.