Brain Teasers
Standing in a Line
Many people are standing in a line. Each can only see the person directly in front of him. The person at the front cannot see anyone. The person at the back of the line is married, while the one at the front is unmarried. Can a married person see an unmarried person?
Answer
Yes, at least one married person can see an unmarried person.If the person directly in front of the person at the back of the line is unmarried, then we have a married person who can see an unmarried person. If he is married, we go to the person in front of him.
If this person is unmarried, then we have a married person who can see an unmarried person. If he is married, we can go to the person in front of him.
Continuing in this manner, we can determine that if the person directly behind the person at the front is unmarried, then there is at least one married person behind him who can see an unmarried person. If this person is married, then since he can see the person at the front, we have a married person who can see an unmarried person.
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