In a room we have 20 people who either lie, tell the truth or are uncertain. Those who tell the truth always tell the truth; those who lie always lie; and those who are uncertain randomly tell the truth at times and lie at other times.
Everyone in this group of 20 people says that there is at least 1 liar among them. Find the number of liars, the number of individuals who tell the truth, and the number of those who are uncertain.
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Send your answer to firstname.lastname@example.org by 5:30 p.m. on December 23, or visit ieee.bilkent.edu.tr/zeka to submit your answer online, and get a chance to win the prize!
This question was prepared by Emrehan Halıcı, president of the Turkey Intelligence Foundation