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?
Since there is a contradiction between the Statements of M and D, it follows that exactly one among M and D is the Knight while the other is a Liar..
Since, M correctly stated this fact, it follows that he is the Knight, so that, D must be the Liar.
Consequently, Mohammad is the knight while Drew is the Liar.
Solution To The Problem
