Consider the following premises. Mary is sad if and only if Jennifer is a taxi driver. Robert is playing squash or it is sunny. Robert is not playing squash or Mary is sad. Jennifer is a taxi driver or it is not sunny. Can we infer the following from them? Jennifer is not a taxi driver.
 From the fact that Mary is sad if and only if Jennifer is a taxi driver we can infer that if Mary were sad, then Jennifer is a taxi driver. From the fact that Jennifer is a taxi driver or it is not sunny we can infer that if it is sunny, then Jennifer is a taxi driver. From the fact that Robert is playing squash or it is sunny, and that Robert is not playing squash or Mary is sad we can infer that it is sunny or Mary is sad. Finally, from the fact that if it is sunny, then Jennifer is a taxi driver, that if Mary were sad, then Jennifer is a taxi driver, and that it is sunny or Mary is sad we can infer that Jennifer is a taxi driver, which contradicts that Jennifer is not a taxi driver. Therefore, the answer is no.