Question 100
A company consists of $7$ Persons, and each $6$ Of them can sit at a round table so that each two neighbors would be familiar to each other. prove that all $7$ Persons can sit at a round table with the same property to be satisfied. (S. Volchenkov) In a company of seven people, any six can sit at a round table so that every two neighbors will be familiar. Prove that the whole company can be seated at a round table so that every two neighbors will turn out to be familiar. (S. Volchenkov)