Consider the following premises. David is climbing a mountain. If Robert drives a car, then Karen is a bartender. If Karen were a bartender, then Robert is driving a car. If Robert drives a car, then David is not climbing a mountain. Can we infer the following from them? Karen is a bartender.
 From the fact that if Karen were a bartender, then Robert is driving a car, and that if Robert drives a car, then Karen is a bartender we can infer that Karen is a bartender if and only if Robert is driving a car. From the fact that if Robert drives a car, then David is not climbing a mountain, and that David is climbing a mountain we can infer that Robert is not driving a car. Finally, from the fact that Karen is a bartender if and only if Robert is driving a car, and that Robert is not driving a car we can infer that Karen is not a bartender, which contradicts that Karen is a bartender. Therefore, the answer is no.