Consider the following premises. It is sunny if and only if it is overcast. It is overcast if and only if Karen is a mechanic. Charles is writing a letter if and only if Karen is a mechanic. It is sunny if and only if James is making tea. Charles is not writing a letter. Can we infer the following from them? James is making tea.
 From the fact that Charles is writing a letter if and only if Karen is a mechanic, and that Charles is not writing a letter we can infer that Karen is not a mechanic. From the fact that it is overcast if and only if Karen is a mechanic, and that Karen is not a mechanic we can infer that it is not overcast. From the fact that it is sunny if and only if it is overcast, and that it is not overcast we can infer that it is not sunny. Finally, from the fact that it is sunny if and only if James is making tea, and that it is not sunny we can infer that James is not making tea, which contradicts that James is making tea. Therefore, the answer is no.