If two people are of the same type,then they are either both knights or both liars.
If they are of different types,then one is a knight and one is a liar.
Now, suppose Drew and Mohammad say the following.
Drew: We are of the same type.
Mohammad: We are of different types.
Now, what are each?
Case 1: Both Drew and Mohammad are Liars. Then Drew obviously cannot say: "We are of the same type". So, both of them are not Liars.
Case 2: Both Drew and Mohammad are Truth Tellers.
In that case Mohammad cannot say: " We are of different types". So, both of them are not Truth Tellers.
Case 3: Drew is a Truth Teller and Mohammad is a Liar. Then Mohammad cannot say: "We are of different types". So, this is also not a possibility.
Case 4: Drew is a Liar and Mohammad is a Truth Teller. It is in this case only when Drew can say: " We are of the same type" and Mohammad can say: " We are of different types".
So, this is what each of them is:
Drew: LIAR
Mohammad: Truth Teller
Solution
