Draw Venn diagrams to show that AB is not necessarily the sa

Draw Venn diagrams to show that A\\B is not necessarily the same as B\\ A. (Knights and knaves). The island of knights and knaves has just two kinds of inhabitants; knights who only make true statements, and knaves who only make false ones. On the island of knights and knaves, you encounter three inhabitants, A, B, and C. A says, \"If I\'m a knight then at least one of us is a knave.\" Can we determine the nature of A? (I.e. whether he is a knight or a knave.) Justify your answer either with truth tables, or the rules of logic, or a combination of both.

Solution

let us assume that A is knave, then A\'s statement is false then neither of them is knave. which contradicts his statement ==> A is knave