Consider the following premises. If it is cloudy, then David is a bartender. It is cloudy if and only if it is snowing. If David were a bartender, then it is snowing. Can we infer the following from them? If we can, name the inference rule being used: The fact that it snows does not imply that David is a bartender.
 From the fact that it is cloudy if and only if it is snowing we can infer that if it snows, then it is cloudy via biconditional elimination. Finally, from the fact that if it snows, then it is cloudy, and that if it is cloudy, then David is a bartender we can infer that if it snows, then David is a bartender via transitivity, which contradicts that The fact that it snows does not imply that David is a bartender. Therefore, the answer is no.