1971 Canadian MO Problems/Problem 10

Problem

Suppose that people each know exactly one piece of information, and all pieces are different. Every time person phones person , tells everything that knows, while tells nothing. What is the minimum number of phone calls between pairs of people needed for everyone to know everything? Prove your answer is a minimum.

Solution

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See Also

1971 Canadian MO (Problems)
Preceded by Problem 9	1 • 2 • 3 • 4 • 5 • 6 • 7 • 8 •	Followed by Last Question