Homework on §1.4--assigned Fri 9/2 and due Mon 9/5

For each of the following claims of entailment, describe a counterexample (that is, a possible world that shows the claim is false)

(i) φ, ψ ⇒ χ
(ii) ψ, χ ⇒ θ

Could one possible world serve as counterexample to both claims? (Say why or why not.)