Consider the following premises. Thomas is working if and only if Elisabeth is a taxi driver. Thomas is not working. If Susan drives a car, then Elisabeth is a taxi driver. Robert is playing squash if and only if Susan is driving a car. Can we infer the following from them? Robert is not playing squash.
 From the fact that Thomas is working if and only if Elisabeth is a taxi driver, and that Thomas is not working we can infer that Elisabeth is not a taxi driver. From the fact that if Susan drives a car, then Elisabeth is a taxi driver, and that Elisabeth is not a taxi driver we can infer that Susan is not driving a car. Finally, from the fact that Robert is playing squash if and only if Susan is driving a car, and that Susan is not driving a car we can infer that Robert is not playing squash. Therefore, the answer is yes.