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IKMC 2014 - Grades 11-12 - Self-study Question 8

IKMC · IKMC 2014 - Grades 11-12 - Self-study

Question 8

Handsome Fritz has a secret email address known only to four friends. Today he received eight emails there. Which statement must be true?
  1. Two emails came from each friend.
  2. All eight cannot come from one friend.
  3. At least one came from every friend.
  4. At least two came from one friend.
  5. At least two came from each of at least two friends.