- #1
Archinald
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Hi
1. Homework Statement
On the party came n people. In the beginning all of them have had exactly 3 friends among party members. During party some people made new friends and at the end of the party everyone had exactly 4 friends among party members. Set all numbers n for which the following statement is true. (if person A knows person B, then person B knows person A)
I found only some law that says -> "In any party of six people either at least three of them are (pairwise) mutual strangers or at least three of them are (pairwise) mutual acquaintances.", but I don't have an idea how to use that to solve this. Making combinations of possible cases i feel like it has to be n > 6 but i have no clue how to prove that.
Thanks in advance for all tips,
mfg
1. Homework Statement
On the party came n people. In the beginning all of them have had exactly 3 friends among party members. During party some people made new friends and at the end of the party everyone had exactly 4 friends among party members. Set all numbers n for which the following statement is true. (if person A knows person B, then person B knows person A)
Homework Equations
The Attempt at a Solution
I found only some law that says -> "In any party of six people either at least three of them are (pairwise) mutual strangers or at least three of them are (pairwise) mutual acquaintances.", but I don't have an idea how to use that to solve this. Making combinations of possible cases i feel like it has to be n > 6 but i have no clue how to prove that.
Thanks in advance for all tips,
mfg