# Knights and Knaves B: “B is a knight only if A is a knight”

I was wondering if someone could help me with this question in Logic.

There are two types of inhabitants on an island: One consists of knights, who always tell the truth and the other consists of knaves, who only lie.

You meet two inhabitants:

B: "B is a knight only if A is a knight" A: says nothing

Who is a knight and who is a knave?

• I'm sure this question has been asked before – Shailesh Jan 19 '16 at 1:45
• There isn't a question here. – Sean English Jan 19 '16 at 2:34

Bearing mind "$p$ only if $q$" means "if $p$ then $q$", try making a truth table:
$\begin{array}{c|c|c|l}\text{A is knight}&\text{B is knight}&\text{(B is knight) implies (A is knight)}&\text{Can B say statement}\\&&&\text{ in last column?}\\\hline F&F&?\\F&T&?\\T&F&?\\T&T&?\\\end{array}$