Consider the following premises. If it snows, then it is raining. Thomas is a taxi driver if and only if Sarah is taking a plane. If Thomas were a taxi driver, then it is raining. It is snowing. Can we infer the following from them? If we can, name the inference rule being used: It is not raining.
 From the fact that Thomas is a taxi driver if and only if Sarah is taking a plane we can infer that if Sarah takes a plane, then Thomas is a taxi driver via biconditional elimination. From the fact that if Sarah takes a plane, then Thomas is a taxi driver, and that if Thomas were a taxi driver, then it is raining we can infer that if Sarah takes a plane, then it is raining via transitivity. From the fact that it is snowing we can infer that it is snowing or Sarah is taking a plane via addition. Finally, from the fact that if it snows, then it is raining, that if Sarah takes a plane, then it is raining, and that it is snowing or Sarah is taking a plane we can infer that it is raining via disjunction elimination, which contradicts that It is not raining. Therefore, the answer is no.