Consider the following premises. Charles is drinking water if and only if Robert is a bartender. If Charles drinks water, then Jessica is a musician. If Jessica were a musician, then Robert is a bartender. Can we infer the following from them? If we can, name the inference rule being used: The fact that Robert were a bartender does not imply that Jessica is a musician.
 From the fact that Charles is drinking water if and only if Robert is a bartender we can infer that if Robert were a bartender, then Charles is drinking water via biconditional elimination. Finally, from the fact that if Robert were a bartender, then Charles is drinking water, and that if Charles drinks water, then Jessica is a musician we can infer that if Robert were a bartender, then Jessica is a musician via transitivity, which contradicts that The fact that Robert were a bartender does not imply that Jessica is a musician. Therefore, the answer is no.